Linux command exit script

Any way to exit bash script, but not quitting the terminal

When I use exit command in a shell script, the script will terminate the terminal (the prompt). Is there any way to terminate a script and then staying in the terminal? My script run.sh is expected to execute by directly being sourced, or sourced from another script. EDIT: To be more specific, there are two scripts run2.sh as

when I run it by . run2.sh , and if it hit exit codeline in run.sh , I want it to stop to the terminal and stay there. But using exit , the whole terminal gets closed. PS: I have tried to use return , but echo codeline will still gets executed.

the exit command should not terminate your terminal session/login. if you use exit 0 to terminate the script after success, when you run your script ex: ./test.sh you should see the output but your console will remain open.

You could use the shell command, that opens in fact a shell terminal. My own experience however is that this doesn’t happen with exit . Exit normally gives back the control to the parent script.

This makes no sense to me. It only kills process (aka the terminal) if called from the top level (globally.) And why would you do that? At the top level, it exits gracefully by itself after completing anyway. Am I missing something here?

@IgnacioVazquez-Abrams your comment does little except to make the OP feel bad. It sort of hints that the problem has to do with sourcing the script, but why not just say that instead of making someone feel bad for trying it? After all, it’s a kind of subtle point that exec and source run differently in terms of shell. Ah, but I see that five people have joined you in being mean.

17 Answers 17

The «problem» really is that you’re sourcing and not executing the script. When you source a file, its contents will be executed in the current shell, instead of spawning a subshell. So everything, including exit, will affect the current shell.

Instead of using exit , you will want to use return .

Although correct, this is not a great answer. It ignores that the calling script may declare variables or functions that that called script needs access to. Better to explain how to set a return code and then process it in runs.sh @ruakh has the better answer to this question.

What if the function is a nested call? i.e. a calls b, b calls c, c wants to immediately exit a and b.

Source is almost the same as copy paste. It’s better to use sh

Yes; you can use return instead of exit . Its main purpose is to return from a shell function, but if you use it within a source -d script, it returns from that script.

Cause a shell function to exit with the return value n. If n is not supplied, the return value is the exit status of the last command executed in the function. This may also be used to terminate execution of a script being executed with the . (or source ) builtin, returning either n or the exit status of the last command executed within the script as the exit status of the script. Any command associated with the RETURN trap is executed before execution resumes after the function or script. The return status is non-zero if return is used outside a function and not during the execution of a script by . or source .

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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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Команда exit в Bash и коды выхода

Часто при написании сценариев Bash вам необходимо завершить сценарий при выполнении определенного условия или выполнить действие на основе кода выхода команды.

В этой статье мы рассмотрим встроенную команду exit Bash и статусы выхода выполненных команд.

Статус выхода

Каждая команда оболочки возвращает код выхода, когда она завершается успешно или безуспешно.

По соглашению нулевой код выхода указывает, что команда завершилась успешно, а ненулевое значение означает, что произошла ошибка.

Специальная переменная $? возвращает статус выхода последней выполненной команды:

Команда date завершена успешно, код выхода равен нулю:

Если вы попытаетесь запустить ls в несуществующем каталоге, код выхода будет отличным от нуля:

ls /nonexisting_dir &> /dev/nullecho $?

Код состояния можно использовать для выяснения причины сбоя команды. На странице руководства каждой команды содержится информация о кодах выхода.

При выполнении многокомандного конвейера статус выхода конвейера соответствует состоянию последней команды:

sudo tcpdump -n -l | tee file.outecho $?

В приведенном выше примере echo $? напечатает код выхода команды tee .

Команда exit

Команда exit закрывает оболочку со статусом N Он имеет следующий синтаксис:

Если N не задано, код состояния выхода — это код последней выполненной команды.

При использовании в сценариях оболочки значение, указанное в качестве аргумента команды exit возвращается оболочке как код выхода.

Примеры

Статус выхода команд может использоваться в условных командах, таких как if . В следующем примере grep завершит работу с нулем (что означает истину в сценариях оболочки), если «строка поиска» найдена в filename :

if grep -q "search-string" filename then echo "String found." else echo "String not found." fi 

При запуске списка команд, разделенных && (И) или || (ИЛИ), статус выхода команды определяет, будет ли выполнена следующая команда в списке. Здесь команда mkdir будет выполнена, только если cd вернет ноль:

cd /opt/code && mkdir project

Если сценарий завершается exit без указания параметра, код выхода из сценария — это код последней команды, выполненной в сценарии.

#!/bin/bash echo "doing stuff. " exit 

Использование только exit — это то же самое, что и exit $? или пропуская exit .

Вот пример, показывающий, как завершить сценарий, если он запущен пользователем без полномочий root:

#!/bin/bash if [[ "$(whoami)" != root ]]; then echo "Only user root can run this script." exit 1 fi echo "doing stuff. " exit 0 

Если вы запустите сценарий как root, код выхода будет нулевым. В противном случае скрипт выйдет со статусом 1 .

Выводы

Каждая команда оболочки возвращает код выхода при завершении. Команда exit используется для выхода из оболочки с заданным статусом.

Если у вас есть какие-либо вопросы или отзывы, не стесняйтесь оставлять комментарии.

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