Shell-operator is a tool for running event-driven scripts in a Kubernetes cluster

深入探索精选的套壳站和必备API资源。本文为初学者和经验丰富的运营者提供一站式指南，涵盖常见问题解答和基础攻略，助您迈向套壳站副业成功之路。Dive into a curated selection of shell sites and essential APIs. This article offers a comprehensive guide for both beginners and seasoned operators, covering FAQs and basic strategies to propel you towards success in your shell site side hustle.

Shark's shell/python scripts for "Airport" operator

Formation DevOps DevOps avec Linux, Shell, Git/GitHub, AWS et CI/CD, Jenkins, Terraform, K8s, Ansible, ArgoCD, Projet, Helm, Operator

The Natural Language Shell integrates OpenAI's GPTs, Anthropic's Claude, or local GGUF-formatted LLMs directly into the terminal experience, allowing operators to describe their tasks in either POSIX commands or fluent human language

Overload the pipe operator (`|`) to provide Elixir/F#/Shell-like behavior

SEIS 665 Assignment 2: Linux & Git Overview This week we will focus on becoming familiar with launching a Linux server and working with some basic Linux and Git commands. We will use AWS to launch and host the Linux server. AWS might seem a little confusing at this point. Don’t worry, we will gain much more hands-on experience with AWS throughout the course. The goal is to get you comfortable working with the technology and not overwhelm you with all the details. Requirements You need to have a personal AWS account and GitHub account for this assignment. You should also read the Git Hands-on Guide and Linux Hands-on Guide before beginning this exercise. A word about grading One of the key DevOps practices we learn about in this class is the use of automation to increase the speed and repeatability of processes. Automation is utilized during the assignment grading process to review and assess your work. It’s important that you follow the instructions in each assignment and type in required files and resources with the proper names. All names are case sensitive, so a name like "Web1" is not the same as "web1". If you misspell a name, use the wrong case, or put a file in the wrong directory location you will lose points on your assignment. This is the easiest way to lose points, and also the most preventable. You should always double-check your work to make sure it accurately reflects the requirements specified in the assignment. You should always carefully review the content of your files before submitting your assignment. The assignment Let’s get started! Create GitHub repository The first step in the assignment is to setup a Git repository on GitHub. We will use a special solution called GitHub Classroom for this course which automates the process of setting up student assignment repositories. Here are the basic steps: Click on the following link to open Assignment 2 on the GitHub Classroom site: https://classroom.github.com/a/K4zcVmX- (Links to an external site.)Links to an external site. Click on the Accept this assignment button. GitHub Classroom will provide you with a URL (https) to access the assignment repository. Either copy this address to your clipboard or write it down somewhere. You will need to use this address to set up the repository on a Linux server. Example: https://github.com/UST-SEIS665/hw2-seis665-02-spring2019-<your github id>.git At this point your new repository to ready to use. The repository is currently empty. We will put some content in there soon! Launch Linux server The second step in the assignment is to launch a Linux server using AWS EC2. The server should have the following characteristics: Amazon Linux 2 AMI 64-bit (usually the first option listed) Located in a U.S. region (us-east-1) t2.micro instance type All default instance settings (storage, vpm, security group, etc.) I’ve shown you how to launch EC2 instances in class. You can review it on Canvas. Once you launch the new server, it may take a few minutes to provision. Log into server The next step is to log into the Linux server using a terminal program with a secure shell (SSH) support. You can use iTerm2 (Links to an external site.)Links to an external site. on a Mac and GitBash/PuTTY (Links to an external site.)Links to an external site. on a PC. You will need to have the private server key and the public IP address before attempting to log into the server. The server key is basically your password. If you lose it, you will need to terminate the existing instance and launch a new server. I recommend reusing the same key when launching new servers throughout the class. Note, I make this recommendation to make the learning process easier and not because it is a common security practice. I’ve shown you how to use a terminal application to log into the instance using a Windows desktop. Your personal computer or lab computer may be running a different OS version, but the process is still very similar. You can review the videos on the Canvas. Working with Linux If you’ve made it this far, congratulations! You’ve made it over the toughest hurdle. By the end of this course, I promise you will be able to launch and log into servers in your sleep. You should be looking at a login screen that looks something like this: Last login: Mon Mar 21 21:17:54 2016 from 174-20-199-194.mpls.qwest.net __| __|_ ) _| ( / Amazon Linux AMI ___|\___|___| https://aws.amazon.com/amazon-linux-ami/2015.09-release-notes/ 8 package(s) needed for security, out of 17 available Run "sudo yum update" to apply all updates. ec2-user@ip-172-31-15-26 ~]$ Your terminal cursor is sitting at the shell prompt, waiting for you to type in your first command. Remember the shell? It is a really cool program that lets you start other programs and manage services on the Linux system. The rest of this assignment will be spent working with the shell. Note, when you are asked to type in a command in the steps below, don’t type in the dollar-sign ($) character. This is just meant to represent the command prompt. The actual commands are represented by the characters to the right of the command prompt. Let’s start by asking the shell for some help. Type in: $ help The shell provides you with a list of commands you can run along with possible command options. Next, check out one of the pages in the built-in manual: $ man ls A man page will appear with information on how to use the ls command. This command is used to list the contents of file directories. Either space through the contents of the man page or hit q to exit. Most of the core Linux commands have man pages available. But honestly, some of these man pages are a bit hard to understand. Sometimes your best bet is to search on Google if you are trying to figure out how to use a specific command. When you initially log into Linux, the system places you in your home directory. Each user on the system has a separate home directory. Let’s see where your home directory is located: $ pwd The response should be /home/ec2-user. The pwd command is handy to remember if you ever forget what file directory you are currently located in. If you recall from the Linux Hands-on Guide, this directory is also your current working directory. Type in: $ cd / The cd command let’s you change to a new working directory on the server. In this case, we changed to the root (/) directory. This is the parent of all the other directories on the file system. Type in: $ ls The ls command lists the contents of the current directory. As you can see, root directory contains many other directories. You will become familiar with these directories over time. The ls command provides a very basic directory listing. You need to supply the command with some options if you want to see more detailed information. Type in: $ ls -la See how this command provides you with much more detailed information about the files and directories? You can use this detailed listing to see the owner, group, and access control list settings for each file or directory. Do you see any files listed? Remember, the first character in the access control list column denotes whether a listed item is a file or a directory. You probably see a couple files with names like .autofsck. How come you didn’t see this file when you typed in the lscommand without any options? (Try to run this command again to convince yourself.) Files names that start with a period are called hidden files. These files won’t appear on normal directory listings. Type in: $ cd /var Then, type in: $ ls You will see a directory listing for the /var directory. Next, type in: $ ls .. Huh. This directory listing looks the same as the earlier root directory listing. When you use two periods (..) in a directory path that means you are referring to the parent directory of the current directory. Just think of the two dots as meaning the directory above the current directory. Now, type in: $ cd ~ $ pwd Whoa. We’re back at our home directory again. The tilde character (~) is another one of those handy little directory path shortcuts. It always refers to our personal home directory. Keep in mind that since every user has their own home directory, the tilde shortcut will refer to a unique directory for each logged-in user. Most students are used to navigating a file system by clicking a mouse in nested graphical folders. When they start using a command-line to navigate a file system, they sometimes get confused and lose track of their current position in the file system. Remember, you can always use the pwd command to quickly figure out what directory you are currently working in. Let’s make some changes to the file system. We can easily make our own directories on the file system. Type: mkdir test Now type: ls Cool, there’s our new test directory. Let’s pretend we don’t like that directory name and delete it. Type: rmdir test Now it’s gone. How can you be sure? You should know how to check to see if the directory still exists at this point. Go ahead and check. Let’s create another directory. Type in: $ mkdir documents Next, change to the new directory: $ cd documents Did you notice that your command prompt displays the name of the current directory? Something like: [ec2-user@ip-172-31-15-26 documents]$. Pretty handy, huh? Okay, let’s create our first file in the documents directory. This is just an empty file for training purposes. Type in: $ touch paper.txt Check to see that the new file is in the directory. Now, go back to the previous directory. Remember the double dot shortcut? $ cd .. Okay, we don’t like our documents directory any more. Let’s blow it away. Type in: $ rmdir documents Uh oh. The shell didn’t like that command because the directory isn’t empty. Let’s change back into the documents directory. But this time don’t type in the full name of the directory. You can let shell auto-completion do the typing for you. Type in the first couple characters of the directory name and then hit the tab key: $ cd doc<tab> You should use the tab auto-completion feature often. It saves typing and makes working with the Linux file system much much easier. Tab is your friend. Now, remove the file by typing: $ rm paper.txt Did you try to use the tab key instead of typing in the whole file name? Check to make sure the file was deleted from the directory. Next, create a new file: $ touch file1 We like file1 so much that we want to make a backup copy. Type: $ cp file1 file1-backup Check to make sure the new backup copy was created. We don’t really like the name of that new file, so let’s rename it. Type: $ mv file1-backup backup Moving a file to the same directory and giving it a new name is basically the same thing as renaming it. We could have moved it to a different directory if we wanted. Let’s list all of the files in the current directory that start with the letter f: $ ls f* Using wildcard pattern matching in file commands is really useful if you want the command to impact or filter a group of files. Now, go up one directory to the parent directory (remember the double dot shortcut?) We tried to remove the documents directory earlier when it had files in it. Obviously that won’t work again. However, we can use a more powerful command to destroy the directory and vanquish its contents. Behold, the all powerful remove command: $ rm -fr documents Did you remember to use auto-completion when typing in documents? This command and set of options forcibly removes the directory and its contents. It’s a dangerous command wielded by the mightiest Linux wizards. Okay, maybe that’s a bit of an exaggeration. Just be careful with it. Check to make sure the documents directory is gone before proceeding. Let’s continue. Change to the directory /var and make a directory called test. Ugh. Permission denied. We created this darn Linux server and we paid for it. Shouldn’t we be able to do anything we want on it? You logged into the system as a user called ec2-user. While this user can create and manage files in its home directory, it cannot change files all across the system. At least it can’t as a normal user. The ec2-user is a member of the root group, so it can escalate its privileges to super-user status when necessary. Let’s try it: $ sudo mkdir test Check to make sure the directory exists now. Using sudo we can execute commands as a super-user. We can do anything we want now that we know this powerful new command. Go ahead and delete the test directory. Did you remember to use sudo before the rmdir command? Check to make sure the directory is gone. You might be asking yourself the question: why can we list the contents of the /var directory but not make changes? That’s because all users have read access to the /var directory and the ls command is a read function. Only the root users or those acting as a super-user can write changes to the directory. Let’s go back to our home directory: $ cd ~ Editing text files is a really common task on Linux systems because many of the application configuration files are text files. We can create a text file by using a text editor. Type in: $ nano myfile.conf The shell starts up the nano text editor and places your terminal cursor in the editing screen. Nano is a simple text-based word processor. Type in a few lines of text. When you’re done writing your novel, hit ctrl-x and answer y to the prompt to save your work. Finally, hit enter to save the text to the filename you specified. Check to see that your file was saved in the directory. You can take a look at the contents of your file by typing: $ cat myfile.conf The cat command displays your text file content on the terminal screen. This command works fine for displaying small text files. But if your file is hundreds of lines long, the content will scroll down your terminal screen so fast that you won’t be able to easily read it. There’s a better way to view larger text files. Type in: $ less myfile.conf The less command will page the display of a text file, allowing you to page through the contents of the file using the space bar. Your text file is probably too short to see the paging in action though. Hit q to quit out of the less text viewer. Hit the up-arrow key on your keyboard a few times until the commmand nano myfile.conf appears next to your command prompt. Cool, huh? The up-arrow key allows you to replay a previously run command. Linux maintains a list of all the commands you have run since you logged into the server. This is called the command history. It’s a really useful feature if you have to re-run a complex command again. Now, hit ctrl-c. This cancels whatever command is displayed on the command line. Type in the following command to create a couple empty files in the directory: $ touch file1 file2 file3 Confirm that the files were created. Some commands, like touch. allow you to specify multiple files as arguments. You will find that Linux commands have all kinds of ways to make tasks more efficient like this. Throughout this assignment, we have been running commands and viewing results on the terminal screen. The screen is the standard place for commands to output results. It’s known as the standard out (stdout). However, it’s really useful to output results to the file system sometimes. Type in: $ ls > listing.txt Take a look at the directory listing now. You just created a new file. View the contents of the listing.txt file. What do you see? Instead of sending the output from the ls command to the screen we sent it to a text file. Let’s try another one. Type: $ cat myfile.conf > listing.txt Take a look at the contents of the listing.txt file again. It looks like your myfile.conf file now. It’s like you made a copy of it. But what happened to the previous content in the listing.txt file? When you redirect the output of a command using the right angle-bracket character (>), the output overwrites the existing file. Type this command in: $ cat myfile.conf >> listing.txt Now look at the contents of the listing.txt file. You should see your original content displayed twice. When you use two angle-bracket characters in the commmand the output appends (or adds to) the file instead of overwriting it. We redirected the output from a command to a text file. It’s also possible to redirect the input to a command. Typically we use a keyboard to provide input, but sometimes it makes more sense to input a file to a command. For example, how many words are in your new listing.txt file? Let’s find out. Type in: $ wc -w < listing.txt Did you get a number? This command inputs the listing.txt file into a word count program called wc. Type in the command: $ ls /usr/bin The terminal screen probably scrolled quickly as filenames flashed by. The /usr/bin directory holds quite a few files. It would be nice if we could page through the contents of this directory. Well, we can. We can use a special shell feature called pipes. In previous steps, we redirected I/O using the file system. Pipes allow us to redirect I/O between programs. We can redirect the output from one program into another. Type in: $ ls /usr/bin | less Now the directory listing is paged. Hit the spacebar to page through the listing. The pipe, represented by a vertical bar character (|), takes the output from the ls command and redirects it to the less command where the resulting output is paged. Pipes are super powerful and used all the time by savvy Linux operators. Hit the q key to quit the paginated directory listing command. Working with shell scripts Now things are going to get interesting. We’ve been manually typing in commands throughout this exercise. If we were running a set of repetitive tasks, we would want to automate the process as much as possible. The shell makes it really easy to automate tasks using shell scripts. The shell provides many of the same features as a basic procedural programming language. Let’s write some code. Type in this command: $ j=123 $ echo $j We just created a variable named j referencing the string 123. The echo command printed out the value of the variable. We had to use a dollar sign ($) when referencing the variable in another command. Next, type in: $ j=1+1 $ echo $j Is that what you expected? The shell just interprets the variable value as a string. It’s not going to do any sort of computation. Typing in shell script commands on the command line is sort of pointless. We want to be able to create scripts that we can run over-and-over. Let’s create our first shell script. Use the nano editor to create a file named myscript. When the file is open in the editor, type in the following lines of code: #!/bin/bash echo Hello $1 Now quit the editor and save your file. We can run our script by typing: $ ./myscript World Er, what happened? Permission denied. Didn’t we create this file? Why can’t we run it? We can’t run the script file because we haven’t set the execute permission on the file. Type in: $ chmod u+x myscript This modifies the file access control list to allow the owner of the file to execute it. Let’s try to run the command again. Hit the up-arrow key a couple times until the ./myscript World command is displayed and hit enter. Hooray! Our first shell script. It’s probably a bit underwhelming. No problem, we’ll make it a little more complex. The script took a single argument called World. Any arguments provided to a shell script are represented as consecutively numbered variables inside the script ($1, $2, etc). Pretty simple. You might be wondering why we had to type the ./ characters before the name of our script file. Try to type in the command without them: $ myscript World Command not found. That seems a little weird. Aren’t we currently in the directory where the shell script is located? Well, that’s just not how the shell works. When you enter a command into the shell, it looks for the command in a predefined set of directories on the server called your PATH. Since your script file isn’t in your special path, the shell reports it as not found. By typing in the ./ characters before the command name you are basically forcing the shell to look for your script in the current directory instead of the default path. Create another file called cleanup using nano. In the file editor window type: #!/bin/bash # My cleanup script mkdir archive mv file* archive Exit the editor window and save the file. Change the permissions on the script file so that you can execute it. Now run the command: $ ./cleanup Take a look at the file directory listing. Notice the archive directory? List the contents of that directory. The script automatically created a new directory and moved three files into it. Anything you can do manually at a command prompt can be automated using a shell script. Let’s create one more shell script. Use nano to create a script called namelist. Here is the content of the script: #!/bin/bash # for-loop test script names='Jason John Jane' for i in $names do echo Hello $i done Change the permissions on the script file so that you can execute it. Run the command: $ ./namelist The script will loop through a set of names stored in a variable displaying each one. Scripts support several programming constructs like for-loops, do-while loops, and if-then-else. These building blocks allow you to create fairly complex scripts for automating tasks. Installing packages and services We’re nearing the end of this assignment. But before we finish, let’s install some new software packages on our server. The first thing we should do is make sure all the current packages installed on our Linux server are up-to-date. Type in: $ sudo yum update -y This is one of those really powerful commands that requires sudo access. The system will review the currently installed packages and go out to the Internet and download appropriate updates. Next, let’s install an Apache web server on our system. Type in: $ sudo yum install httpd -y Bam! You probably never knew that installing a web server was so easy. We’re not going to actually use the web server in this exercise, but we will in future assignments. We installed the web server, but is it actually running? Let’s check. Type in: $ sudo service httpd status Nope. Let’s start it. Type: $ sudo service httpd start We can use the service command to control the services running on the system. Let’s setup the service so that it automatically starts when the system boots up. Type in: $ sudo chkconfig httpd on Cool. We installed the Apache web server on our system, but what other programs are currently running? We can use the pscommand to find out. Type in: $ ps -ax Lots of processes are running on our system. We can even look at the overall performance of our system using the topcommand. Let’s try that now. Type in: $ top The display might seem a little overwhelming at first. You should see lots of performance information displayed including the cpu usage, free memory, and a list of running tasks. We’re almost across the finish line. Let’s make sure all of our valuable work is stored in a git repository. First, we need to install git. Type in the command: $ sudo yum install git -y Check your work It’s very important to check your work before submitting it for grading. A misspelled, misplaced or missing file will cost you points. This may seem harsh, but the reality is that these sorts of mistakes have consequences in the real world. For example, a server instance could fail to launch properly and impact customers because a single required file is missing. Here is what the contents of your git repository should look like before final submission: ┣archive ┃ ┣ file1 ┃ ┣ file2 ┃ ┗ file3 ┣ namelist ┗ myfile.conf Saving our work in the git repository Next, make sure you are still in your home directory (/home/ec2-user). We will install the git repository you created at the beginning of this exercise. You will need to modify this command by typing in the GitHub repository URL you copied earlier. $ git clone <your GitHub URL here>.git Example: git clone https://github.com/UST-SEIS665/hw2-seis665-02-spring2019-<your github id>.git The git application will ask you for your GitHub username and password. Note, if you have multi-factor authentication enabled on your GitHub account you will need to provide a personal token instead of your password. Git will clone (copy) the repository from GitHub to your Linux server. Since the repository is empty the clone happens almost instantly. Check to make sure that a sub-directory called "hw2-seis665-02-spring2019-<username>" exists in the current directory (where <username> is your GitHub account name). Git automatically created this directory as part of the cloning process. Change to the hw2-seis665-02-spring2019-<username> directory and type: $ ls -la Notice the .git hidden directory? This is where git actually stores all of the file changes in your repository. Nothing is actually in your repository yet. Change back to the parent directory (cd ..). Next, let’s move some of our files into the repository. Type: $ mv archive hw2-seis665-02-spring2019-<username> $ mv namelist hw2-seis665-02-spring2019-<username> $ mv myfile.conf hw2-seis665-02-spring2019-<username> Hopefully, you remembered to use the auto-complete function to reduce some of that typing. Change to the hw2-seis665-02-spring2019-<username> directory and list the directory contents. Your files are in the working directory, but are not actually stored in the repository because they haven’t been committed yet. Type in: $ git status You should see a list of untracked files. Let’s tell git that we want these files tracked. Type in: $ git add * Now type in the git status command again. Notice how all the files are now being tracked and are ready to be committed. These files are in the git staging area. We’ll commit them to the repository next. Type: $ git commit -m 'assignment 2 files' Next, take a look at the commit log. Type: $ git log You should see your commit listed along with an assigned hash (long string of random-looking characters). Finally, let’s save the repository to our GitHub account. Type in: $ git push origin master The git client will ask you for your GitHub username and password before pushing the repository. Go back to the GitHub.com website and login if you have been logged out. Click on the repository link for the assignment. Do you see your files listed there? Congratulations, you completed the exercise! Terminate server The last step is to terminate your Linux instance. AWS will bill you for every hour the instance is running. The cost is nominal, but there’s no need to rack up unnecessary charges. Here are the steps to terminate your instance: Log into your AWS account and click on the EC2 dashboard. Click the Instances menu item. Select your server in the instances table. Click on the Actions drop down menu above the instances table. Select the Instance State menu option Click on the Terminate action. Your Linux instance will shutdown and disappear in a few minutes. The EC2 dashboard will continue to display the instance on your instance listing for another day or so. However, the state of the instance will be terminated. Submitting your assignment — IMPORTANT! If you haven’t already, please e-mail me your GitHub username in order to receive credit for this assignment. There is no need to email me to tell me that you have committed your work to GitHub or to ask me if your GitHub submission worked. If you can see your work in your GitHub repository, I can see your work.

MiniSH is a simple shell like Bash, handling commands, pipes, redirections, subshells, operators (&&, ||, ;), environment variables, and more, built to understand how a shell works at a low level.

Pipex is a project commonly assigned in the curriculum of the 42 coding school. Its main objective is to introduce students to UNIX pipes and inter-process communication. In Pipex, you re-create in C the shell's pipeline operator (`|`), which allows the output of one command to be used as the input for another command.

rxjs operators for execute shell command with ease

No description available

In this assignment you will write smallsh your own shell in C. smallsh will implement a subset of features of well-known shells, such as bash. Your program will Provide a prompt for running commands Handle blank lines and comments, which are lines beginning with the # character Provide expansion for the variable $$ Execute 3 commands exit, cd, and status via code built into the shell Execute other commands by creating new processes using a function from the exec family of functions Support input and output redirection Support running commands in foreground and background processes Implement custom handlers for 2 signals, SIGINT and SIGTSTP Learning Outcomes After successful completion of this assignment, you should be able to do the following Describe the Unix process API (Module 4, MLO 2) Write programs using the Unix process API (Module 4, MLO 3) Explain the concept of signals and their uses (Module 5, MLO 2) Write programs using the Unix API for signal handling (Module 5, MLO 3) Explain I/O redirection and write programs that can employ I/O redirection (Module 5, MLO 4) Program Functionality 1. The Command Prompt Use the colon : symbol as a prompt for each command line. The general syntax of a command line is: command [arg1 arg2 ...] [< input_file] [> output_file] [&] …where items in square brackets are optional. You can assume that a command is made up of words separated by spaces. The special symbols <, > and & are recognized, but they must be surrounded by spaces like other words. If the command is to be executed in the background, the last word must be &. If the & character appears anywhere else, just treat it as normal text. If standard input or output is to be redirected, the > or < words followed by a filename word must appear after all the arguments. Input redirection can appear before or after output redirection. Your shell does not need to support any quoting; so arguments with spaces inside them are not possible. We are also not implementing the pipe "|" operator. Your shell must support command lines with a maximum length of 2048 characters, and a maximum of 512 arguments. You do not need to do any error checking on the syntax of the command line. 2. Comments & Blank Lines Your shell should allow blank lines and comments. Any line that begins with the # character is a comment line and should be ignored. Mid-line comments, such as the C-style //, will not be supported. A blank line (one without any commands) should also do nothing. Your shell should just re-prompt for another command when it receives either a blank line or a comment line. 3. Expansion of Variable $$ Your program must expand any instance of "$$" in a command into the process ID of the smallsh itself. Your shell does not otherwise perform variable expansion. 4. Built-in Commands Your shell will support three built-in commands: exit, cd, and status. These three built-in commands are the only ones that your shell will handle itself - all others are simply passed on to a member of the exec() family of functions. You do not have to support input/output redirection for these built in commands These commands do not have to set any exit status. If the user tries to run one of these built-in commands in the background with the & option, ignore that option and run the command in the foreground anyway (i.e. don't display an error, just run the command in the foreground). exit The exit command exits your shell. It takes no arguments. When this command is run, your shell must kill any other processes or jobs that your shell has started before it terminates itself. cd The cd command changes the working directory of smallsh. By itself - with no arguments - it changes to the directory specified in the HOME environment variable This is typically not the location where smallsh was executed from, unless your shell executable is located in the HOME directory, in which case these are the same. This command can also take one argument: the path of a directory to change to. Your cd command should support both absolute and relative paths. status The status command prints out either the exit status or the terminating signal of the last foreground process ran by your shell. If this command is run before any foreground command is run, then it should simply return the exit status 0. The three built-in shell commands do not count as foreground processes for the purposes of this built-in command - i.e., status should ignore built-in commands. 5. Executing Other Commands Your shell will execute any commands other than the 3 built-in command by using fork(), exec() and waitpid() Whenever a non-built in command is received, the parent (i.e., smallsh) will fork off a child. The child will use a function from the exec() family of functions to run the command. Your shell should use the PATH variable to look for non-built in commands, and it should allow shell scripts to be executed If a command fails because the shell could not find the command to run, then the shell will print an error message and set the exit status to 1 A child process must terminate after running a command (whether the command is successful or it fails). 6. Input & Output Redirection You must do any input and/or output redirection using dup2(). The redirection must be done before using exec() to run the command. An input file redirected via stdin should be opened for reading only; if your shell cannot open the file for reading, it should print an error message and set the exit status to 1 (but don't exit the shell). Similarly, an output file redirected via stdout should be opened for writing only; it should be truncated if it already exists or created if it does not exist. If your shell cannot open the output file it should print an error message and set the exit status to 1 (but don't exit the shell). Both stdin and stdout for a command can be redirected at the same time (see example below). 7. Executing Commands in Foreground & Background Foreground Commands Any command without an & at the end must be run as a foreground command and the shell must wait for the completion of the command before prompting for the next command. For such commands, the parent shell does NOT return command line access and control to the user until the child terminates. Background Commands Any non built-in command with an & at the end must be run as a background command and the shell must not wait for such a command to complete. For such commands, the parent must return command line access and control to the user immediately after forking off the child. The shell will print the process id of a background process when it begins. When a background process terminates, a message showing the process id and exit status will be printed. This message must be printed just before the prompt for a new command is displayed. If the user doesn't redirect the standard input for a background command, then standard input should be redirected to /dev/null If the user doesn't redirect the standard output for a background command, then standard output should be redirected to /dev/null 8. Signals SIGINT & SIGTSTP SIGINT A CTRL-C command from the keyboard sends a SIGINT signal to the parent process and all children at the same time (this is a built-in part of Linux). Your shell, i.e., the parent process, must ignore SIGINT Any children running as background processes must ignore SIGINT A child running as a foreground process must terminate itself when it receives SIGINT The parent must not attempt to terminate the foreground child process; instead the foreground child (if any) must terminate itself on receipt of this signal. If a child foreground process is killed by a signal, the parent must immediately print out the number of the signal that killed it's foreground child process (see the example) before prompting the user for the next command. SIGTSTP A CTRL-Z command from the keyboard sends a SIGTSTP signal to your parent shell process and all children at the same time (this is a built-in part of Linux). A child, if any, running as a foreground process must ignore SIGTSTP. Any children running as background process must ignore SIGTSTP. When the parent process running the shell receives SIGTSTP The shell must display an informative message (see below) immediately if it's sitting at the prompt, or immediately after any currently running foreground process has terminated The shell then enters a state where subsequent commands can no longer be run in the background. In this state, the & operator should simply be ignored, i.e., all such commands are run as if they were foreground processes. If the user sends SIGTSTP again, then your shell will Display another informative message (see below) immediately after any currently running foreground process terminates The shell then returns back to the normal condition where the & operator is once again honored for subsequent commands, allowing them to be executed in the background. See the example below for usage and the exact syntax which you must use for these two informative messages. Sample Program Execution Here is an example run using smallsh. Note that CTRL-C has no effect towards the bottom of the example, when it's used while sitting at the command prompt: $ smallsh : ls junk smallsh smallsh.c : ls > junk : status exit value 0 : cat junk junk smallsh smallsh.c : wc < junk > junk2 : wc < junk 3 3 23 : test -f badfile : status exit value 1 : wc < badfile cannot open badfile for input : status exit value 1 : badfile badfile: no such file or directory : sleep 5 ^Cterminated by signal 2 : status & terminated by signal 2 : sleep 15 & background pid is 4923 : ps PID TTY TIME CMD 4923 pts/0 00:00:00 sleep 4564 pts/0 00:00:03 bash 4867 pts/0 00:01:32 smallsh 4927 pts/0 00:00:00 ps : : # that was a blank command line, this is a comment line : background pid 4923 is done: exit value 0 : # the background sleep finally finished : sleep 30 & background pid is 4941 : kill -15 4941 background pid 4941 is done: terminated by signal 15 : pwd /nfs/stak/users/chaudhrn/CS344/prog3 : cd : pwd /nfs/stak/users/chaudhrn : cd CS344 : pwd /nfs/stak/users/chaudhrn/CS344 : echo 4867 4867 : echo $$ 4867 : ^C^Z Entering foreground-only mode (& is now ignored) : date Mon Jan 2 11:24:33 PST 2017 : sleep 5 & : date Mon Jan 2 11:24:38 PST 2017 : ^Z Exiting foreground-only mode : date Mon Jan 2 11:24:39 PST 2017 : sleep 5 & background pid is 4963 : date Mon Jan 2 11:24:39 PST 2017 : exit $ Hints & Resources 1. The Command Prompt Be sure you flush out the output buffers each time you print, as the text that you're outputting may not reach the screen until you do in this kind of interactive program. To do this, call fflush() immediately after each and every time you output text. Consider defining a struct in which you can store all the different elements included in a command. Then as you parse a command, you can set the value of members of a variable of this struct type. 2. Comments & Blank Lines This should be simple. 3. Expansion of Variable $$ Here are examples to illustrate the required behavior. Suppose the process ID of smallsh is 179. Then The string foo$$$$ in the command is converted to foo179179 The string foo$$$ in the command is converted to foo179$ 4. Built-in Commands It is recommended that you program the built-in commands first, before tackling the commands that require fork(), exec() and waitpid(). The built-in commands don't set the value of status. This means that however you are keeping track of the status, don't change it after the execution of a built-in command. A process can use chdir() (Links to an external site.) to change its directory. To test the implementation of the cd command in smallsh, don't use getenv("PWD") because it will not give you the correct result. Instead, you can use the function getcwd() (Links to an external site.). Here is why getenv("PWD") doesn't give you the correct result: PWD is an environment variable. As discussed in Module 4, Exploration: Environment "When a parent process forks a child process, the child process inherits the environment of its parent process." When you run smallsh from a bash shell, smallsh inherits the environment of this bash shell The value of PWD in the bash shell is set to the directory in which you are when you run the command to start smallsh smallsh inherits this value of PWD. When you change the directory in smallsh, it doesn't update the value of the environment variable PWD 5. Executing Other Commands Note that if exec() is told to execute something that it cannot do, like run a program that doesn't exist, it will fail, and return the reason why. In this case, your shell should indicate to the user that a command could not be executed (which you know because exec() returned an error), and set the value retrieved by the built-in status command to 1. Make sure that the child process that has had an exec() call fail terminates itself, or else it often loops back up to the top and tries to become a parent shell. This is easy to spot: if the output of the grading script seems to be repeating itself, then you've likely got a child process that didn't terminate after a failed exec(). You can choose any function in the exec() family. However, we suggest that using either execlp() or execvp() will be simplest because of the following reasons smallsh doesn't need to pass a new environment to the program. So the additional functionality provided by the exec() functions with names ending in e is not required. One example of a command that smallsh needs to run is ls (the graders will try this command at the start of the testing). Running this command will be a lot easier using the exec() functions that search the PATH environment variable. 6. Input & Output Redirection We recommend that the needed input/output redirection should be done in the child process. Note that after using dup2() to set up the redirection, the redirection symbol and redirection destination/source are NOT passed into the exec command For example, if the command given is ls > junk, then you handle the redirection to "junk" with dup2() and then simply pass ls into exec(). 7. Executing Commands in Foreground & Background Foreground Commands For a foreground command, it is recommend to have the parent simply call waitpid() on the child, while it waits. Background Commands The shell should respect the input and output redirection operators for a command regardless of whether the command is to be run in the foreground or the background. This means that a background command should use /dev/null for input only when input redirection is not specified in the command. Similarly a background command should use /dev/null for output only when output redirection is not specified in the command. Your parent shell will need to periodically check for the background child processes to complete, so that they can be cleaned up, as the shell continues to run and process commands. Consider storing the PIDs of non-completed background processes in an array. Then every time BEFORE returning access to the command line to the user, you can check the status of these processes using waitpid(...NOHANG...). Alternatively, you may use a signal handler to immediately wait() for child processes that terminate, as opposed to periodically checking a list of started background processes The time to print out when these background processes have completed is just BEFORE command line access and control are returned to the user, every time that happens. 8. Signals SIGINT & SIGTSTP Reentrancy is important when we consider that signal handlers cause jumps in execution that cause problems with certain functions. Note that the printf() family of functions is NOT reentrant. In your signal handlers, when outputting text, you must use other output functions! What to turn in? You can only use C for coding this assignment and you must use the gcc compiler. You can use C99 or GNU99 standard or the default standard used by the gcc installation on os1. Your assignment will be graded on os1. Submit a single zip file with all your code, which can be in as many different files as you want. This zip file must be named youronid_program3.zip where youronid should be replaced by your own ONID. E.g., if chaudhrn was submitting the assignment, the file must be named chaudhrn_program3.zip. In the zip file, you must include a text file called README.txt that contains instructions on how to compile your code using gcc to create an executable file that must be named smallsh. Your zip file should not contain any extraneous files. In particular, make sure not to zip up the __MACOSX directories. When you resubmit a file in Canvas, Canvas can attach a suffix to the file, e.g., the file name may become chaudhrn_program3-1.zip. Don't worry about this name change as no points will be deducted because of this. Caution During the development of this program, take extra care to only do your work on os1, our class server, as your software will likely negatively impact whatever machine it runs on, especially before it is finished. If you cause trouble on one of the non-class, public servers, it could hurt your grade! If you are having trouble logging in to any of our EECS servers because of runaway processes, please use this page to kill off any programs running on your account that might be blocking your access: T.E.A.C.H. - The Engineering Accounts and Classes HomepageLinks to an external site. Grading Criteria This assignment is worth 20% of your grade and there are 180 points available for it. 170 points are available in the test script, while the final 10 points will be based on your style, readability, and commenting. Comment well, often, and verbosely: we want to see that you are telling us WHY you are doing things, in addition to telling us WHAT you are doing. Once the program is compiled, according to your specifications given in README.txt, your shell will be executed to run a few sample commands against (ls, status, exit, in that order). If the program does not successfully work on those commands, it will receive a zero. If it works, then the grading script will be run against it (as detailed below) for final grading. Points will be assigned according to the grading script running on our class server only. Grading Method Here is the grading script p3testscript. It is a bash script that starts the smallsh program and runs commands on smallsh's command line. Most of the commands run by the grading script are very similar to the commands shown in the section Sample Program Execution. You can open the script in a text editor. The comments in the script will show you the points for individual items. Use the script to prepare for your grade, as this is how it's being earned. To run the script, place it in the same directory as your compiled shell, chmod it (chmod +x ./p3testscript) and run this command from a bash prompt: $ ./p3testscript 2>&1 or $ ./p3testscript 2>&1 | more or $ ./p3testscript > mytestresults 2>&1 Do not worry if the spacing, indentation, or look of the output of the script is different than when you run it interactively: that won’t affect your grade. The script may add extra colons at the beginning of lines or do other weird things, like put output about terminating processes further down the script than you intended. If your program does not work with the grading script, and you instead request that we grade your script by hand, we will apply a 15% reduction to your final score. So from the very beginning, make sure that you work with the grading script on our class server!

Install Prometheus Operator by shell scripts

A minimal Unix-like shell supporting command execution, piping, redirections (>, <, >>), background execution (&), logical operators (&&, ||), and command history (!n).

Custom Unix shell with pipes, redirections, logical operators, and subshell support.

Some hints and example shell scripts about the use of CDO (Climate Data Operators).

The MultiversX blockchain (formerly Elrond) offers amazing user-experiences, so mxConsole was created to both augment the standard node operation shell, and to provide a smoother environment for new node operators.

# Trybe This repository contains all the learning activities developed by João V.S Dias https://www.linkedin.com/in/diasvictorj/_ while studying at [Trybe](https://www.betrybe.com/) :rocket: _"Trybe is a school of the future for anyone who wants to improve their life and build a successful career in technology, where people only pay when they get a good job."_ The program has more than 1,500 hours of classroom and online classes, covers an introduction to software development, front-end, back-end, computer science, software engineering, agile methodologies and behavioral skills. ## Web Development Fundamentals :white_check_mark: ##### Block 1: Introduction - Unix & Shell - [ ] 1-3: _Unix & Shell- Part 1_ - [ ] 1-4: _Unix & Shell- Part 2_ ##### Block 2: Git & GitHub - [ ] 2-1: _What is it and what is it for?_ - [ ] 2-2: _Understanding the commands_ - [ ] 2-3: _Internet - Understanding how it works_ ##### Block 3: Introduction - HTML & CSS - [ ] 3-1: _HTML & CSS - Page Structures_ - [ ] 3-2: _HTML & CSS - Getting Started with CSS_ - [ ] 3-3: _HTML & CSS - Selectors and positioning_ - [ ] 3-4: _Semantic HTML_ - [ ] 3-5: _[Project - HTML & CSS]()_ ##### Block 4: Introduction - JavaScript - [ ] 4-1: _JavaScript - First steps_ - [ ] 4-2: _JavaScript - Array and For_ loop - [ ] 4-3: _JavaScript - Programming Logic and Algorithms_ - [ ] 4-4: _JavaScript - Objects and Functions_ - [ ] 4-5: _[Project - Playground Functions]()_ ##### Block 5: Introduction - JavaScript - Projects - [ ] 5-1: _JavaScript - DOM and selectors_ - [ ] 5-2: _JavaScript - Working with elements_ - [ ] 5-3: _JavaScript - Events_ - [ ] 5-4: _JavaScript - Web Storage_ - [ ] 5-5: _[Project - Meme Generator]()_ - [ ] 5-6: _[Project - Pixel Art]()_ - [ ] 5-7: _[Project - Task List]()_ - [ ] 5-7: _[Project - Guess the Color]()_ - [ ] 5-7: _[Project - Mysterious Letter]()_ ##### Block 6: Advanced HTML & CSS - [ ] 6-1: _HTML & CSS - Forms_ - [ ] 6-2: _JavaScript Libraries and CSS Frameworks_ - [ ] 6-3: _CSS Flexbox - Part 1_ - [ ] 6-4: _CSS Flexbox - Part 2_ - [ ] 6-5: _CSS Responsive - Mobile First_ - [ ] 6-6: _[Project - Facebook homepage]()_ ##### Block 7: JavaScript ES6 & Unit Tests - [ ] 7-1: _JavaScript ES6 - let, const, arrow functions and template literals_ - [ ] 7-2: _JavaScript ES6 - Objects_ - [ ] 7-3: _Unit tests in JavaScript_ - [ ] 7-4: _[Project - JavaScript Unit Tests]()_ ##### Block 8: JavaScript ES6 - [ ] 8-1: _JavaScript ES6 - Higher Order Functions - forEach, find, some, every, sort_ - [ ] 8-2: _JavaScript ES6 - Higher Order Functions - map and filter_ - [ ] 8-3: _JavaScript ES6 - Higher Order Functions - reduce_ - [ ] 8-4: _JavaScript ES6 - spread operator, rest parameter, destructuring and more_ - [ ] 8-5: _[Project - Zoo functions]()_ ##### Block 9: Asynchronicity & Callbacks - [ ] 9-1: _Asynchronous JavaScript and Callbacks_ - [ ] 9-2: _JavaScript Promises_ - [ ] 9-3: _[Project - Shopping Cart]()_ ##### Block 10: Jest - [ ] 10-1: _First steps in Jest_ - [ ] 10-2: _Jest - Asynchronous Tests_ - [ ] 10-3: _Jest - Simulating behavior_ - [ ] 10-4: _[Project - Asynchronous Jest and Mocking]()_ ## Front-end development :hourglass_flowing_sand: ##### Block 11: Introduction - React - [ ] 11-1: _'Hello, world!' on React!_ - [ ] 11-2: _React Components_ - [ ] 11-3: _[Project - Movie Cards Library]()_ ##### Block 12: React - [ ] 12-1: _Components with status_ - [ ] 12-2: _Events and forms in React_ - [ ] 12-3: _[Project - Movie Cards Library Stateful]()_ ##### Block 13: React - [ ] 13-1: _Improving component reuse: props.children and PropTypes_ - [ ] 13-2: _Component lifecycle in React_ - [ ] 13-3: _React Router_ - [ ] 13-4: _[Project - Movie Cards Library CRUD]()_ ##### Block 14: Agile Methodologies - [ ] 14-1: _Agile Methodologies_ - [ ] 14-2: _[Project - Frontend Online Store]()_ ##### Block 15: Tests in React - [ ] 15-1: _Testing React with the React Testing Library_ - [ ] 15-2: _Testing React with the React Testing Library - Part 2_ - [ ] 15-3: _[Project - Tests in React]()_ ##### Block 16: Introduction to Redux - [ ] 16-1: _Introduction to Redux_ - [ ] 16-2: _React with Redux - Part 1_ - [ ] 16-3: _React with Redux - Practice_ - [ ] 16-4: _React with Redux - Part 2_ - [ ] 16-5: _Synchronous tests with React-Redux_ - [ ] 16-6: _[Project - Table with data filters]()_ ##### Block 17: Project React - [ ] 17-1: _[Project - Trivia Game]()_ ##### Block 18: React & Context API - [ ] 18-1: _Context API of React_ - [ ] 18-2: _React Hooks - useState and useContext_ - [ ] 18-3: _React Hooks - useEffect and Custom Hooks_ - [ ] 18-4: _[Project - StarWars Datatable with Context API and Hooks]()_ ##### Block 19: Front-end Final Project - [ ] 19-1: _[Project - Recipe App]()_ ## Back-end Development :hourglass_flowing_sand: ##### Block 20: Introduction - Relational Databases - [ ] 20-1: _SQL Database_ - [ ] 20-2: _Finding data in a database_ - [ ] 20-3: _Filtering data specifically_ - [ ] 20-4: _Manipulating tables_ - [ ] 20-5: _[Project - All For One]()_ ##### Block 21: Relational Databases - [ ] 21-1: _Most used functions in SQL_ - [ ] 21-2: _Uncomplicating JOINs and UNIONs_ - [ ] 21-3: _Stored Routines & Subqueries_ - [ ] 21-4: _[Project - Vocabulary Booster]()_ ##### Block 22: Relational Databases - [ ] 22-1: _Transforming ideas into a database model_ - [ ] 22-2: _Normalization, Normal Forms and Dumps_ - [ ] 22-2: _Turning ideas into a database model - Part 2_ - [ ] 22-3: _[Project - One For All]()_ ##### Block 23: Introduction - NoSQL - [ ] 23-1: _MongoDB - Introduction_ - [ ] 23-2: _Filter Operators_ - [ ] 23-3: _[Project - Date Flights]()_ ##### Block 24: Updates - [ ] 24-1: _Simple Updates_ - [ ] 24-2: _Complex Updates - Arrays - Part 1_ - [ ] 24-3: _Complex Updates - Arrays - Part 2_ - [ ] 24-4: _[Project - Commerce]()_ ##### Block 25: Aggregation Framework - [ ] 25-1: _Aggregation Framework - Part 1_ - [ ] 25-2: _Aggregation Framework - Part 2_ - [ ] 25-3: _[Project - Aggregations]()_ ##### Block 26: Intro - NodeJS - [ ] 26-1: _NodeJS - Introduction_ - [ ] 26-2: _NodeJS - Asynchronous Flow_ - [ ] 26-3: _NodeJS - Architecture_ - [ ] 26-4: _[Project - A CLI of Ice and Fire]()_ ##### Block 27: NodeJS - [ ] 27-1: _Express: HTTP with Node.js_ - [ ] 27-2: _Software Architecture - Introduction to MVC_ - [ ] 27-3: _[Project - Cookmaster]()_ ##### Block 28: NodeJS - [ ] 28-1: _Software Architecture - Service Layer_ - [ ] 28-2: _Web Architecture - Rest and Restful_ - [ ] 28-3: _[Project - Store Manager]()_ ##### Block 29: NodeJS - [ ] 29-1: _NodeJS - JWT - (JSON Web Token)_ - [ ] 29-2: _NodeJS - Upload files with Multer_ - [ ] 29-3: _[Project - Cookmaster V2]()_ ##### Block 30: Introduction - Deploy - [ ] 30-1: _Infrastructure - Deploy with Heroku_ - [ ] 30-2: _Deploy - Process Managers_ - [ ] 30-3: _[Project - Stranger Things]()_ ##### Block 31: Project - [ ] 31-1: _[Project - Trybeer]()_ ##### Block 32: Software Architecture - [ ] 32-1: _Architecture - SOLID Principles_ - [ ] 32-2: _ORM - Application interface with the database_ - [ ] 32-3: _Software Architecture - DDD_ - [ ] 32-4: _Good practice writing tests_ - [ ] 32-3: _[Project - Blogs API]()_ ##### Block 33: Sockets - [ ] 30-1: _Sockets - TCP/UDP & NET_ - [ ] 30-2: _Sockets - Socket.io_ - [ ] 30-3: _[Project - Webchat]()_ ##### Block 34: Project - [ ] 34-1: _[Project - Trybeer V2]()_ ## Computer Science :hourglass_flowing_sand: ##### Block 35: Introduction - Computer Science - [ ] 35-1: _Computer Architecture_ - [ ] 35-2: _Network architecture_ - [ ] 35-3: _Computer networks, tools and security_ - [ ] 35-4: _[Project - Exploring the protocols]()_ ##### Block 36: Python - [ ] 35-1: _Learning Python_ - [ ] 35-2: _Tests and Exceptions_ - [ ] 35-3: _Data Input and Output_ - [ ] 36-4: _Data Input and Output_ - [ ] 35-5: _[Project - Tech news]()_ # [...]

tool for implement kubernetes controller/operator by shell scripts

Complete Shell Scripting notes & assignments — Basics, Variables, Operators, Strings, Conditionals, Loops, and Arrays. Beginner-friendly with 19 hands-on practice problems.

A Project that recreates the functionality of the | operator in the shell, which is used to pipe the output of one command as the input to another command.

Write a beautiful code that passes the Betty checks Repo: GitHub repository: simple_shell 1. Simple shell 0.1 mandatory Write a UNIX command line interpreter. Usage: simple_shell Your Shell should: Display a prompt and wait for the user to type a command. A command line always ends with a new line. The prompt is displayed again each time a command has been executed. The command lines are simple, no semicolons, no pipes, no redirections or any other advanced features. The command lines are made only of one word. No arguments will be passed to programs. If an executable cannot be found, print an error message and display the prompt again. Handle errors. You have to handle the “end of file” condition (Ctrl+D) You don’t have to: use the PATH implement built-ins handle special characters : ", ', `, \, *, &, # be able to move the cursor handle commands with arguments julien@ubuntu:~/shell$ ./shell #cisfun$ ls ./shell: No such file or directory #cisfun$ /bin/ls barbie_j env-main.c exec.c fork.c pid.c ppid.c prompt prompt.c shell.c stat.c wait env-environ.c exec fork mypid ppid printenv promptc shell stat test_scripting.sh wait.c #cisfun$ /bin/ls -l ./shell: No such file or directory #cisfun$ ^[[D^[[D^[[D ./shell: No such file or directory #cisfun$ ^[[C^[[C^[[C^[[C ./shell: No such file or directory #cisfun$ exit ./shell: No such file or directory #cisfun$ ^C julien@ubuntu:~/shell$ echo "/bin/ls" | ./shell #cisfun$ barbie_j env-main.c exec.c fork.c pid.c ppid.c prompt prompt.c shell.c stat.c wait env-environ.c exec fork mypid ppid printenv promptc shell stat test_scripting.sh wait.c #cisfun$ julien@ubuntu:~/shell$ Repo: GitHub repository: simple_shell 2. Simple shell 0.2 mandatory Simple shell 0.1 + Handle command lines with arguments Repo: GitHub repository: simple_shell 3. Simple shell 0.3 mandatory Simple shell 0.2 + Handle the PATH fork must not be called if the command doesn’t exist julien@ubuntu:~/shell$ ./shell_0.3 :) /bin/ls barbie_j env-main.c exec.c fork.c pid.c ppid.c prompt prompt.c shell_0.3 stat test_scripting.sh wait.c env-environ.c exec fork mypid ppid printenv promptc shell shell.c stat.c wait :) ls barbie_j env-main.c exec.c fork.c pid.c ppid.c prompt prompt.c shell_0.3 stat test_scripting.sh wait.c env-environ.c exec fork mypid ppid printenv promptc shell shell.c stat.c wait :) ls -l /tmp total 20 -rw------- 1 julien julien 0 Dec 5 12:09 config-err-aAMZrR drwx------ 3 root root 4096 Dec 5 12:09 systemd-private-062a0eca7f2a44349733e78cb4abdff4-colord.service-V7DUzr drwx------ 3 root root 4096 Dec 5 12:09 systemd-private-062a0eca7f2a44349733e78cb4abdff4-rtkit-daemon.service-ANGvoV drwx------ 3 root root 4096 Dec 5 12:07 systemd-private-062a0eca7f2a44349733e78cb4abdff4-systemd-timesyncd.service-CdXUtH -rw-rw-r-- 1 julien julien 0 Dec 5 12:09 unity_support_test.0 :) ^C julien@ubuntu:~/shell$ Repo: GitHub repository: simple_shell 4. Simple shell 0.4 mandatory Simple shell 0.3 + Implement the exit built-in, that exits the shell Usage: exit You don’t have to handle any argument to the built-in exit Repo: GitHub repository: simple_shell 5. Simple shell 1.0 mandatory Simple shell 0.4 + Implement the env built-in, that prints the current environment julien@ubuntu:~/shell$ ./simple_shell $ env USER=julien LANGUAGE=en_US SESSION=ubuntu COMPIZ_CONFIG_PROFILE=ubuntu SHLVL=1 HOME=/home/julien C_IS=Fun_:) DESKTOP_SESSION=ubuntu LOGNAME=julien TERM=xterm-256color PATH=/home/julien/bin:/home/julien/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin DISPLAY=:0 $ exit julien@ubuntu:~/shell$ Repo: GitHub repository: simple_shell 6. Simple shell 0.1.1 #advanced Simple shell 0.1 + Write your own getline function Use a buffer to read many chars at once and call the least possible the read system call You will need to use static variables You are not allowed to use getline You don’t have to: be able to move the cursor Repo: GitHub repository: simple_shell 7. Simple shell 0.2.1 #advanced Simple shell 0.2 + You are not allowed to use strtok Repo: GitHub repository: simple_shell 8. Simple shell 0.4.1 #advanced Simple shell 0.4 + handle arguments for the built-in exit Usage: exit status, where status is an integer used to exit the shell julien@ubuntu:~/shell$ ./shell_0.4.1 $ exit 98 julien@ubuntu:~/shell$ echo $? 98 julien@ubuntu:~/shell$ Repo: GitHub repository: simple_shell 9. setenv, unsetenv #advanced Simple shell 1.0 + Implement the setenv and unsetenv builtin commands setenv Initialize a new environment variable, or modify an existing one Command syntax: setenv VARIABLE VALUE Should print something on stderr on failure unsetenv Remove an environment variable Command syntax: unsetenv VARIABLE Should print something on stderr on failure Repo: GitHub repository: simple_shell 10. cd #advanced Simple shell 1.0 + Implement the builtin command cd: Changes the current directory of the process. Command syntax: cd [DIRECTORY] If no argument is given to cd the command must be interpreted like cd $HOME You have to handle the command cd - You have to update the environment variable PWD when you change directory man chdir, man getcwd Repo: GitHub repository: simple_shell 11. ; #advanced Simple shell 1.0 + Handle the commands separator ; alex@~$ ls /var ; ls /var backups cache crash lib local lock log mail metrics opt run spool tmp backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ ls /hbtn ; ls /var ls: cannot access /hbtn: No such file or directory backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ ls /var ; ls /hbtn backups cache crash lib local lock log mail metrics opt run spool tmp ls: cannot access /hbtn: No such file or directory alex@~$ ls /var ; ls /hbtn ; ls /var ; ls /var backups cache crash lib local lock log mail metrics opt run spool tmp ls: cannot access /hbtn: No such file or directory backups cache crash lib local lock log mail metrics opt run spool tmp backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ Repo: GitHub repository: simple_shell 12. && and || #advanced Simple shell 1.0 + Handle the && and || shell logical operators alex@~$ ls /var && ls /var backups cache crash lib local lock log mail metrics opt run spool tmp backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ ls /hbtn && ls /var ls: cannot access /hbtn: No such file or directory alex@~$ ls /var && ls /var && ls /var && ls /hbtn backups cache crash lib local lock log mail metrics opt run spool tmp backups cache crash lib local lock log mail metrics opt run spool tmp backups cache crash lib local lock log mail metrics opt run spool tmp ls: cannot access /hbtn: No such file or directory alex@~$ ls /var && ls /var && ls /var && ls /hbtn && ls /hbtn backups cache crash lib local lock log mail metrics opt run spool tmp backups cache crash lib local lock log mail metrics opt run spool tmp backups cache crash lib local lock log mail metrics opt run spool tmp ls: cannot access /hbtn: No such file or directory alex@~$ alex@~$ ls /var || ls /var backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ ls /hbtn || ls /var ls: cannot access /hbtn: No such file or directory backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ ls /hbtn || ls /hbtn || ls /hbtn || ls /var ls: cannot access /hbtn: No such file or directory ls: cannot access /hbtn: No such file or directory ls: cannot access /hbtn: No such file or directory backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ ls /hbtn || ls /hbtn || ls /hbtn || ls /var || ls /var ls: cannot access /hbtn: No such file or directory ls: cannot access /hbtn: No such file or directory ls: cannot access /hbtn: No such file or directory backups cache crash lib local lock log mail metrics opt run spool tmp alex@~$ Repo: GitHub repository: simple_shell 13. alias #advanced Simple shell 1.0 + Implement the alias builtin command Usage: alias [name[='value'] ...] alias: Prints a list of all aliases, one per line, in the form name='value' alias name [name2 ...]: Prints the aliases name, name2, etc 1 per line, in the form name='value' alias name='value' [...]: Defines an alias for each name whose value is given. If name is already an alias, replaces its value with value Repo: GitHub repository: simple_shell 14. Variables #advanced Simple shell 1.0 + Handle variables replacement Handle the $? variable Handle the $$ variable julien@ubuntu:~/shell$ ./hsh $ ls /var backups cache crash lib local lock log mail metrics opt run snap spool tmp $ echo $? 0 $ echo $$ 5104 $ echo $PATH /home/julien/bin:/home/julien/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin $ exit julien@ubuntu:~/shell$ Repo: GitHub repository: simple_shell 15. Comments #advanced Simple shell 1.0 + Handle comments (#) julien@ubuntu:~/shell$ sh $ echo $$ # ls -la 5114 $ exit julien@ubuntu:~/shell$ Repo: GitHub repository: simple_shell 16. File as input #advanced Simple shell 1.0 + Usage: simple_shell [filename] Your shell can take a file as a command line argument The file contains all the commands that your shell should run before exiting The file should contain one command per line In this mode, the shell should not print a prompt and should not read from stdin Repo: GitHub repository: simple_shell

Turn an AAS (Asset Administration Shell) JSON page or a pasted/uploaded AAS JSON into a simple equipment card with manuals, safety docs, and contacts inside Chrome’s side panel (so operators/maintenance don’t have to read raw JSON).

SPECTRA is a program for high precision paramagnetic ions energy levels calculations based on crystal field multipole method (CFMM) and the method of irreducible tensor operators. It allows to calculate the electronic structure of all elements with unfilled f-shells, including lanthanides and actinides in crystalline hosts and nano-structures. It can be used in scientific research, educational institutions, industry (laser materials, chemical analysis etc). Written in Fortran-90 for MS with IMSL.

In this assignment you will write smallsh your own shell in C. smallsh will implement a subset of features of well-known shells, such as bash. Your program will Provide a prompt for running commands Handle blank lines and comments, which are lines beginning with the # character Provide expansion for the variable $$ Execute 3 commands exit, cd, and status via code built into the shell Execute other commands by creating new processes using a function from the exec family of functions Support input and output redirection Support running commands in foreground and background processes Implement custom handlers for 2 signals, SIGINT and SIGTSTP Learning Outcomes After successful completion of this assignment, you should be able to do the following Describe the Unix process API (Module 4, MLO 2) Write programs using the Unix process API (Module 4, MLO 3) Explain the concept of signals and their uses (Module 5, MLO 2) Write programs using the Unix API for signal handling (Module 5, MLO 3) Explain I/O redirection and write programs that can employ I/O redirection (Module 5, MLO 4) Program Functionality 1. The Command Prompt Use the colon : symbol as a prompt for each command line. The general syntax of a command line is: command [arg1 arg2 ...] [< input_file] [> output_file] [&] …where items in square brackets are optional. You can assume that a command is made up of words separated by spaces. The special symbols <, > and & are recognized, but they must be surrounded by spaces like other words. If the command is to be executed in the background, the last word must be &. If the & character appears anywhere else, just treat it as normal text. If standard input or output is to be redirected, the > or < words followed by a filename word must appear after all the arguments. Input redirection can appear before or after output redirection. Your shell does not need to support any quoting; so arguments with spaces inside them are not possible. We are also not implementing the pipe "|" operator. Your shell must support command lines with a maximum length of 2048 characters, and a maximum of 512 arguments. You do not need to do any error checking on the syntax of the command line. 2. Comments & Blank Lines Your shell should allow blank lines and comments. Any line that begins with the # character is a comment line and should be ignored. Mid-line comments, such as the C-style //, will not be supported. A blank line (one without any commands) should also do nothing. Your shell should just re-prompt for another command when it receives either a blank line or a comment line. 3. Expansion of Variable $$ Your program must expand any instance of "$$" in a command into the process ID of the smallsh itself. Your shell does not otherwise perform variable expansion. 4. Built-in Commands Your shell will support three built-in commands: exit, cd, and status. These three built-in commands are the only ones that your shell will handle itself - all others are simply passed on to a member of the exec() family of functions. You do not have to support input/output redirection for these built in commands These commands do not have to set any exit status. If the user tries to run one of these built-in commands in the background with the & option, ignore that option and run the command in the foreground anyway (i.e. don't display an error, just run the command in the foreground). exit The exit command exits your shell. It takes no arguments. When this command is run, your shell must kill any other processes or jobs that your shell has started before it terminates itself. cd The cd command changes the working directory of smallsh. By itself - with no arguments - it changes to the directory specified in the HOME environment variable This is typically not the location where smallsh was executed from, unless your shell executable is located in the HOME directory, in which case these are the same. This command can also take one argument: the path of a directory to change to. Your cd command should support both absolute and relative paths. status The status command prints out either the exit status or the terminating signal of the last foreground process ran by your shell. If this command is run before any foreground command is run, then it should simply return the exit status 0. The three built-in shell commands do not count as foreground processes for the purposes of this built-in command - i.e., status should ignore built-in commands. 5. Executing Other Commands Your shell will execute any commands other than the 3 built-in command by using fork(), exec() and waitpid() Whenever a non-built in command is received, the parent (i.e., smallsh) will fork off a child. The child will use a function from the exec() family of functions to run the command. Your shell should use the PATH variable to look for non-built in commands, and it should allow shell scripts to be executed If a command fails because the shell could not find the command to run, then the shell will print an error message and set the exit status to 1 A child process must terminate after running a command (whether the command is successful or it fails). 6. Input & Output Redirection You must do any input and/or output redirection using dup2(). The redirection must be done before using exec() to run the command. An input file redirected via stdin should be opened for reading only; if your shell cannot open the file for reading, it should print an error message and set the exit status to 1 (but don't exit the shell). Similarly, an output file redirected via stdout should be opened for writing only; it should be truncated if it already exists or created if it does not exist. If your shell cannot open the output file it should print an error message and set the exit status to 1 (but don't exit the shell). Both stdin and stdout for a command can be redirected at the same time (see example below). 7. Executing Commands in Foreground & Background Foreground Commands Any command without an & at the end must be run as a foreground command and the shell must wait for the completion of the command before prompting for the next command. For such commands, the parent shell does NOT return command line access and control to the user until the child terminates. Background Commands Any non built-in command with an & at the end must be run as a background command and the shell must not wait for such a command to complete. For such commands, the parent must return command line access and control to the user immediately after forking off the child. The shell will print the process id of a background process when it begins. When a background process terminates, a message showing the process id and exit status will be printed. This message must be printed just before the prompt for a new command is displayed. If the user doesn't redirect the standard input for a background command, then standard input should be redirected to /dev/null If the user doesn't redirect the standard output for a background command, then standard output should be redirected to /dev/null 8. Signals SIGINT & SIGTSTP SIGINT A CTRL-C command from the keyboard sends a SIGINT signal to the parent process and all children at the same time (this is a built-in part of Linux). Your shell, i.e., the parent process, must ignore SIGINT Any children running as background processes must ignore SIGINT A child running as a foreground process must terminate itself when it receives SIGINT The parent must not attempt to terminate the foreground child process; instead the foreground child (if any) must terminate itself on receipt of this signal. If a child foreground process is killed by a signal, the parent must immediately print out the number of the signal that killed it's foreground child process (see the example) before prompting the user for the next command. SIGTSTP A CTRL-Z command from the keyboard sends a SIGTSTP signal to your parent shell process and all children at the same time (this is a built-in part of Linux). A child, if any, running as a foreground process must ignore SIGTSTP. Any children running as background process must ignore SIGTSTP. When the parent process running the shell receives SIGTSTP The shell must display an informative message (see below) immediately if it's sitting at the prompt, or immediately after any currently running foreground process has terminated The shell then enters a state where subsequent commands can no longer be run in the background. In this state, the & operator should simply be ignored, i.e., all such commands are run as if they were foreground processes. If the user sends SIGTSTP again, then your shell will Display another informative message (see below) immediately after any currently running foreground process terminates The shell then returns back to the normal condition where the & operator is once again honored for subsequent commands, allowing them to be executed in the background. See the example below for usage and the exact syntax which you must use for these two informative messages. Sample Program Execution Here is an example run using smallsh. Note that CTRL-C has no effect towards the bottom of the example, when it's used while sitting at the command prompt: $ smallsh : ls junk smallsh smallsh.c : ls > junk : status exit value 0 : cat junk junk smallsh smallsh.c : wc < junk > junk2 : wc < junk 3 3 23 : test -f badfile : status exit value 1 : wc < badfile cannot open badfile for input : status exit value 1 : badfile badfile: no such file or directory : sleep 5 ^Cterminated by signal 2 : status & terminated by signal 2 : sleep 15 & background pid is 4923 : ps PID TTY TIME CMD 4923 pts/0 00:00:00 sleep 4564 pts/0 00:00:03 bash 4867 pts/0 00:01:32 smallsh 4927 pts/0 00:00:00 ps : : # that was a blank command line, this is a comment line : background pid 4923 is done: exit value 0 : # the background sleep finally finished : sleep 30 & background pid is 4941 : kill -15 4941 background pid 4941 is done: terminated by signal 15 : pwd /nfs/stak/users/chaudhrn/CS344/prog3 : cd : pwd /nfs/stak/users/chaudhrn : cd CS344 : pwd /nfs/stak/users/chaudhrn/CS344 : echo 4867 4867 : echo $$ 4867 : ^C^Z Entering foreground-only mode (& is now ignored) : date Mon Jan 2 11:24:33 PST 2017 : sleep 5 & : date Mon Jan 2 11:24:38 PST 2017 : ^Z Exiting foreground-only mode : date Mon Jan 2 11:24:39 PST 2017 : sleep 5 & background pid is 4963 : date Mon Jan 2 11:24:39 PST 2017 : exit $ Hints & Resources 1. The Command Prompt Be sure you flush out the output buffers each time you print, as the text that you're outputting may not reach the screen until you do in this kind of interactive program. To do this, call fflush() immediately after each and every time you output text. Consider defining a struct in which you can store all the different elements included in a command. Then as you parse a command, you can set the value of members of a variable of this struct type. 2. Comments & Blank Lines This should be simple. 3. Expansion of Variable $$ Here are examples to illustrate the required behavior. Suppose the process ID of smallsh is 179. Then The string foo$$$$ in the command is converted to foo179179 The string foo$$$ in the command is converted to foo179$ 4. Built-in Commands It is recommended that you program the built-in commands first, before tackling the commands that require fork(), exec() and waitpid(). The built-in commands don't set the value of status. This means that however you are keeping track of the status, don't change it after the execution of a built-in command. A process can use chdir() (Links to an external site.) to change its directory. To test the implementation of the cd command in smallsh, don't use getenv("PWD") because it will not give you the correct result. Instead, you can use the function getcwd() (Links to an external site.). Here is why getenv("PWD") doesn't give you the correct result: PWD is an environment variable. As discussed in Module 4, Exploration: Environment "When a parent process forks a child process, the child process inherits the environment of its parent process." When you run smallsh from a bash shell, smallsh inherits the environment of this bash shell The value of PWD in the bash shell is set to the directory in which you are when you run the command to start smallsh smallsh inherits this value of PWD. When you change the directory in smallsh, it doesn't update the value of the environment variable PWD 5. Executing Other Commands Note that if exec() is told to execute something that it cannot do, like run a program that doesn't exist, it will fail, and return the reason why. In this case, your shell should indicate to the user that a command could not be executed (which you know because exec() returned an error), and set the value retrieved by the built-in status command to 1. Make sure that the child process that has had an exec() call fail terminates itself, or else it often loops back up to the top and tries to become a parent shell. This is easy to spot: if the output of the grading script seems to be repeating itself, then you've likely got a child process that didn't terminate after a failed exec(). You can choose any function in the exec() family. However, we suggest that using either execlp() or execvp() will be simplest because of the following reasons smallsh doesn't need to pass a new environment to the program. So the additional functionality provided by the exec() functions with names ending in e is not required. One example of a command that smallsh needs to run is ls (the graders will try this command at the start of the testing). Running this command will be a lot easier using the exec() functions that search the PATH environment variable. 6. Input & Output Redirection We recommend that the needed input/output redirection should be done in the child process. Note that after using dup2() to set up the redirection, the redirection symbol and redirection destination/source are NOT passed into the exec command For example, if the command given is ls > junk, then you handle the redirection to "junk" with dup2() and then simply pass ls into exec(). 7. Executing Commands in Foreground & Background Foreground Commands For a foreground command, it is recommend to have the parent simply call waitpid() on the child, while it waits. Background Commands The shell should respect the input and output redirection operators for a command regardless of whether the command is to be run in the foreground or the background. This means that a background command should use /dev/null for input only when input redirection is not specified in the command. Similarly a background command should use /dev/null for output only when output redirection is not specified in the command. Your parent shell will need to periodically check for the background child processes to complete, so that they can be cleaned up, as the shell continues to run and process commands. Consider storing the PIDs of non-completed background processes in an array. Then every time BEFORE returning access to the command line to the user, you can check the status of these processes using waitpid(...NOHANG...). Alternatively, you may use a signal handler to immediately wait() for child processes that terminate, as opposed to periodically checking a list of started background processes The time to print out when these background processes have completed is just BEFORE command line access and control are returned to the user, every time that happens. 8. Signals SIGINT & SIGTSTP Reentrancy is important when we consider that signal handlers cause jumps in execution that cause problems with certain functions. Note that the printf() family of functions is NOT reentrant. In your signal handlers, when outputting text, you must use other output functions! What to turn in? You can only use C for coding this assignment and you must use the gcc compiler. You can use C99 or GNU99 standard or the default standard used by the gcc installation on os1. Your assignment will be graded on os1. Submit a single zip file with all your code, which can be in as many different files as you want. This zip file must be named youronid_program3.zip where youronid should be replaced by your own ONID. E.g., if chaudhrn was submitting the assignment, the file must be named chaudhrn_program3.zip. In the zip file, you must include a text file called README.txt that contains instructions on how to compile your code using gcc to create an executable file that must be named smallsh. Your zip file should not contain any extraneous files. In particular, make sure not to zip up the __MACOSX directories. When you resubmit a file in Canvas, Canvas can attach a suffix to the file, e.g., the file name may become chaudhrn_program3-1.zip. Don't worry about this name change as no points will be deducted because of this. Caution During the development of this program, take extra care to only do your work on os1, our class server, as your software will likely negatively impact whatever machine it runs on, especially before it is finished. If you cause trouble on one of the non-class, public servers, it could hurt your grade! If you are having trouble logging in to any of our EECS servers because of runaway processes, please use this page to kill off any programs running on your account that might be blocking your access: T.E.A.C.H. - The Engineering Accounts and Classes HomepageLinks to an external site. Grading Criteria This assignment is worth 20% of your grade and there are 180 points available for it. 170 points are available in the test script, while the final 10 points will be based on your style, readability, and commenting. Comment well, often, and verbosely: we want to see that you are telling us WHY you are doing things, in addition to telling us WHAT you are doing. Once the program is compiled, according to your specifications given in README.txt, your shell will be executed to run a few sample commands against (ls, status, exit, in that order). If the program does not successfully work on those commands, it will receive a zero. If it works, then the grading script will be run against it (as detailed below) for final grading. Points will be assigned according to the grading script running on our class server only. Grading Method Here is the grading script p3testscript. It is a bash script that starts the smallsh program and runs commands on smallsh's command line. Most of the commands run by the grading script are very similar to the commands shown in the section Sample Program Execution. You can open the script in a text editor. The comments in the script will show you the points for individual items. Use the script to prepare for your grade, as this is how it's being earned. To run the script, place it in the same directory as your compiled shell, chmod it (chmod +x ./p3testscript) and run this command from a bash prompt: $ ./p3testscript 2>&1 or $ ./p3testscript 2>&1 | more or $ ./p3testscript > mytestresults 2>&1 Do not worry if the spacing, indentation, or look of the output of the script is different than when you run it interactively: that won’t affect your grade. The script may add extra colons at the beginning of lines or do other weird things, like put output about terminating processes further down the script than you intended. If your program does not work with the grading script, and you instead request that we grade your script by hand, we will apply a 15% reduction to your final score. So from the very beginning, make sure that you work with the grading script on our class server!

Learning Objectives At the end of this project, you are expected to be able to explain to anyone, without the help of Google: General Why C programming is awesome (don’t forget to tweet today, with the hashtag #cisfun :)) Who invented C Who are Dennis Ritchie, Brian Kernighan and Linus Torvalds What happens when you type gcc main.c What is an entry point What is main How to print text using printf, puts and putchar How to get the size of a specific type using the unary operator sizeof How to compile using gcc What is the default program name when compiling with gcc What is the official Holberton C coding style and how to check your code with betty-style How to find the right header to include in your source code when using a standard library function How does the main function influence the return value of the program Requirements C Allowed editors: vi, vim, emacs All your files will be compiled on Ubuntu 14.04 LTS using gcc 4.8.4 All your files should end with a new line A README.md file at the root of the holbertonschool-low_level_programming repo, containing a description of the repository A README.md file, at the root of the folder of this project, containing a description of the project There should be no errors and no warnings during compilation You are not allowed to use system Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl Shell Scripts Allowed editors: vi, vim, emacs All your scripts will be tested on Ubuntu 14.04 LTS All your scripts should be exactly two lines long ($ wc -l file should print 2) All your files should end with a new line The first line of all your files should be exactly #!/bin/bash

巧用 shell-operator 配置 K8s Pod 保护策略

Simple Shell Operator for Python

Pipex replicates the Shell Pipe ( | ) operator in C.

Deterministic, resumable workflows for agents, operators, and shells.