How to stop script linux

How to exit sh program?

I bungled the commands and wrote sh -man Now I’ve entered a program called sh-3.2 that is seemingly impossible to exit. Ctrl c , Ctrl z , or Ctrl x does not work. exit , quit , q , : q also does not work. All google answers are for exiting shell scripts programmatically.

5 Answers 5

Ctrl + D does the trick for me.

Actually it is the -n flag that introduces this behaviour. It is meant to do only syntax checking of the commands, but doesn’t actually execute them.

Try ctrl+d that should kill the shell.

Hold Ctrl and press p q . This solved my issue.

If you shell exit is pre planned then use,

Or you can program to handle SIGTERM and other signals a sample tutorial

Or if you want to stop already running shell script

Or find the pid and kill it.

ps -ax | grep shell_name pkill -9 PID_of_shell 

Try also typing ` which is in the same key as ~ on the keyboard, and then press Return . Ctrl + D kills the terminal but ` won’t.

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How do I Exit a Bash Script?

You may have encountered many situations when you have to quit your bash script upon some inconvenience. There are many methods to quit the bash script, i.e., quit while writing a bash script, while execution, or at run time. One of the many known methods to exit a bash script while writing is the simple shortcut key, i.e., “Ctrl+X”. While at run time, you can exit the code using “Ctrl+Z”. This guide will show how the batch script can be quitted using the different exit clauses while executing. Let’s get started by logging in from the Ubuntu 20.04 system first and opening the shell using “Ctrl+Alt+T”.

Example 01: Using Exit 0

The first method we have been utilizing in this example is to use the “exit” statement in the bash script. Create a new file in the shell with the help of a “touch” command and open it in any editor.

The read statement is widely known to get input from the user. Here it will take integer values at run time and save them to the variable “x”. The “if” statement has been checking a condition. If the value of “x” entered by a user is equaled to 5, it will display that the number is matched via the echo statement. The “exit 0” clause has been used here. After executing the “echo” statement, the bash script will be quitted, and no more execution will be performed due to “exit 0”. Otherwise, if the condition doesn’t satisfy, the “echo” statement outside of the “if” statement will be executed.

Run your bash file with the help of a bash query in the shell. The user added 4 as input. As 4 is not equal to 5, it doesn’t run the “then” part of the “if” statement. So, no sudden exit will happen. On the other hand, the echo statement outside of the “if” statement executed states that “Number doesn’t match..” and the program ends here.

Run the same code once again with the bash command. The user added 5 this time. As 5 satisfies the condition, the “echo” statement inside the “then” clause was executed. After that, the program stops quickly due to the use of “exit 0”.

Example 02: Using Exit

Instead of using “exit 0”, you can simply use “exit” in your bash script to exit the code. So, open the same file and update your code. Only the “exit” clause has been changed here, i.e., replaced by “exit”. The whole file remained unchanged. Let’s save the code first using the “Ctrl+S” and quit using “Crl+X”. Let’s execute it to see if it works the same as the “exit 1” clause does or not.

Run the bash file “bash.sh” in the terminal by utilizing the command shown in the attached screenshot. The user entered the value “6” and it didn’t satisfy the condition. Therefore, the compiler ignores the “then” clause of the “if” statement and executes the echo clause outside of the “if” statement.

Run the same file once again. This time the user added 5 as satisfying the condition. Thus the bash script exits right after executing the “echo” clause inside the “if” statement.

Example 03: Using Exit 1

You can also use the “exit” clause to exit the bash script while stating 1 with it at run time. So, open the same file and update your code as we have done before. The only change is “exit 1” instead of “exit” or “exit 0”. Save your code and quit the editor via “Ctrl+S” and “Ctrl+X”.

At first execution, the user added 6 as input. The condition doesn’t satisfy and commands within the “if” statement won’t be executed. So, no sudden exit happened.

On the second attempt, the user added 5 to satisfy the condition. So, the commands within the “if” statement get executed, and the program exits after running the “echo” clause.

Example 04

Let’s make use of the “exit 1” clause in the bash script upon checking different situations. So, we have updated the code of the same file. After the bash support, the “if” statement has been initialized to check if the currently logged-in user, i.e., “Linux” is not the root user. If the condition satisfies, the echo statement within the “then” clause will be executed, and the program will exit right here. If the currently logged-in account is a root user, it will continue to execute the statements outside of the “if” statement. The program will continue to get two inputs from a user and compute the sum of both integers. The calculated “sum” will be displayed, and then the program will exit.

As the “Linux” account is not a root user of our Ubuntu 20.04, the execution of this code has only executed the “if” statement and clauses between it. The program quits after this.

Example 05: Using “set -e” Built-in

The “set –e” built-in is widely known to exit the program upon encountering the non-zero status. So, we have added 3 twin-named functions with 1 echo statement and a return status clause in each. The “set +e” is initialized before calling the first two methods, and “set –e” is used after that, and two functions are called after that.

Upon execution, both show1 and show2 function’s echo statements will run, and the program will not quit. While after “set –e” the program quits after the execution of the show2() method’s echo statement as it encounters “return 1”. The method show3 will not be called after that.

Upon running this code, we got the output as expected. Upon encountering the return 1 status, the program stopped without executing the “show3()” method.

Conclusion

This guide covers all the possible ways to exit any bash script while writing, executing, or running. Thus, try to implement each example covered in this article to get a more clear understanding.

About the author

Omar Farooq

Hello Readers, I am Omar and I have been writing technical articles from last decade. You can check out my writing pieces.

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How to kill a script running in terminal, without closing terminal (Ctrl + C doesn’t work)?

I have written a bash script that calls several other programs and executes a bunch of commands. I run this script from the terminal. Now I want to kill the script. Pressing Ctrl + C sometimes doesn’t cut it, I think because sometimes the script is executing another program, and for some reason the kill signal doesn’t work. However, if I close the terminal window, it kills the script. Is there something I can do (a keyboard combination), that is analogous to closing the terminal window, without actually closing the terminal window (I don’t want to lose command history, current directory, output history, etc.)?

3 Answers 3

You have few options. One is to stop the script ( Ctrl Z ), get the PID of the script and send SIGKILL to the process group.

When a command is executed in a shell, the process it starts and all its children are part of the same process group (in this case, the foreground process group). To send a signal to all processes in this group, you send it to the process leader. For the kill command, process leader is denoted thus:

Where PID is the process ID of the script.

Consider a script test.sh which launches some processes. Say you ran it in a shell:

$ pgrep test.sh 17802 $ pstree -ps `!!` pstree -ps `pgrep test.sh` init(1)───sshd(1211)───sshd(17312)───sshd(17372)───zsh(17788)───test.sh(17802)─┬─dd(17804) ├─sleep(17805) └─yes(17803) 

In this case, to send a signal to process group created by test.sh , you’d do:

-INT is used to send SIGINT , and so this command is the equivalent of pressing Ctrl C on the terminal. To send SIGKILL :

You only need to stop the script if you can’t open another terminal. If you can, use pgrep to find the PID.

One of the commands that the script launches may be trapping SIGINT , which is probably why Ctrl C is ineffective. However, SIGKILL can’t be trapped, and it is usually a last-resort option. You might want to try SIGTERM ( -TERM ) before going for the kill. Neither SIGKILL or SIGTERM can be set up as a keyboard shortcut the way SIGINT is.

All this is moot if your script doesn’t contain a shebang line. From this SO answer:

Usually the parent shell guesses that the script is written for the the same shell (minimal Bourne-like shells run the script with /bin/sh, bash runs it as a bash subprocess) .

Because of this, when the script is executed, you won’t find a process named after script (or a process with the script’s name in the command line) and pgrep will fail.

Always use a shebang line.

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How to manually stop a Python script that runs continuously on linux

I have a Python script that is running and continuously dumping errors into a log file. I want to edit the script and run it again, but don’t know how to stop the script. I’m currently logged on Linux through PuTTy and am doing all the coding there. So, is there a command to stop the python script in linux?

7 Answers 7

You will have to find the process id (pid). one command to do this would be

to limit results to python processes you can grep the result

which will give results like :

user 2430 1 0 Jul03 ? 00:00:01 /usr/bin/python -tt /usr/sbin/yum-updatesd 

the second column is the pid. then use the kill command as such :

$> kill -9 2430 (i.e. the pid returned) 

Try this simple line, It will terminate all script.py :

Find the process id (PID) of the script and issue a kill -9 PID to kill the process unless it’s running as your forground process at the terminal in which case you can Contrl-C to kill it.

Find the PID with this command:

It lists all the python processes, pick out the right one and note its PID. Then

will kill the process. You may get a message about having terminated a process at this stage.

Alternatively, you can use the top command to find the python process. Simply enter k (for kill) and the top program will prompt you for the PID of the process to kill. Sometimes it’s difficult to see all processes you are interested in with top since they may scroll off the screen, I think the ps approach is easier/better.

If the program is the current process in your shell, typing Ctrl-C will stop the Python program.

If you are running a process in a loop it will only kill that process rather than the python script. For example, I have a python script to read URLs from a file, and for each URL it will run youtube-dl to download the video. If I press Ctrl + C it will only kill the youtube-dl process. Then it will move on to the next item.

In a perfect world, you’d read the documentation for the script and see which signal(s) should be used to tell it to end. In real life, you probably want to send it the TERM signal, first, maybe using a KILL signal if it ignores the TERM. So, what you do is find the Process ID, using the ps command (as someone already described). Then, you can run kill -TERM . Some programs will clean up things, like files they might have open, when they get a signal like that, so it’s nicer to start with something like that. If that fails, then there’s not much left to do except the big hammer: kill -KILL . (you can use the numeric values, e.g. -KILL = -9, and they’ll probably never change, but in a theoretical sense it might be safer to use the names)

If you know the name of the script you could reduce all the work to a single command:

ps -ef | grep "script_name" | awk '' | xargs sudo kill 

If you want to make sure that is a python script:

ps -ef | grep "python script_name" | awk '' | xargs sudo kill 

If you wanted to kill all the python scripts:

ps -ef | grep "python" | awk '' | xargs sudo kill 

I suppose you get the idea 😉

Reminder: you need to quote «» the script name as is in the examples.

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