Exit Bash Script With Error
Contents |
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of bash if exit code this site About Us Learn more about Stack Overflow the company Business
Exit Bash Shell
Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask unix exit codes Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign
Linux Exit Code
up In a bash script, how can I exit the entire script if a certain condition occurs? up vote 237 down vote favorite 50 I'm writing a script in Bash to test some code. However, it seems silly to run the tests if compiling the code fails in the first place, in which case I'll just abort the tests. Is there a way shell script exit I can do this without wrapping the entire script inside of a while loop and using breaks? Something like a dun dun dun goto? bash scripting share|improve this question asked Sep 4 '09 at 9:51 samoz 20.8k39109168 add a comment| 6 Answers 6 active oldest votes up vote 225 down vote accepted Try this statement: exit 1 Replace 1 with appropriate error codes. See also Exit Codes With Special Meanings. share|improve this answer edited Aug 7 '15 at 7:10 flying sheep 2,96722245 answered Sep 4 '09 at 9:53 Michael Foukarakis 20.6k35090 42 0 isn't good status to exit with if an error happens. –Michał Górny Sep 4 '09 at 9:59 4 You're right, edited for clarity. –Michael Foukarakis Sep 4 '09 at 10:00 @MichałGórny what would be a good status code? –CMCDragonkai May 14 '14 at 2:39 3 @CMCDragonkai, usually any non-zero code will work. If you don't need anything special, you can just use 1 consistently. If the script is meant to be run by another script, you may want to define your own set of status code with particular m
and Signals and Traps (Oh My!) - Part 1 by William Shotts, Jr. In this lesson, we're going to look at handling errors during the execution of your scripts. The difference between a good program and a poor one is often measured in terms of the program's robustness.
Bash Exit Function
That is, the program's ability to handle situations in which something goes wrong. Exit status As
Bash Return Value From Function
you recall from previous lessons, every well-written program returns an exit status when it finishes. If a program finishes successfully, the exit status will bash not equal be zero. If the exit status is anything other than zero, then the program failed in some way. It is very important to check the exit status of programs you call in your scripts. It is also important that your http://stackoverflow.com/questions/1378274/in-a-bash-script-how-can-i-exit-the-entire-script-if-a-certain-condition-occurs scripts return a meaningful exit status when they finish. I once had a Unix system administrator who wrote a script for a production system containing the following 2 lines of code: # Example of a really bad idea cd $some_directory rm * Why is this such a bad way of doing it? It's not, if nothing goes wrong. The two lines change the working directory to the name contained in $some_directory and delete the files in that directory. That's the intended http://linuxcommand.org/wss0150.php behavior. But what happens if the directory named in $some_directory doesn't exist? In that case, the cd command will fail and the script executes the rm command on the current working directory. Not the intended behavior! By the way, my hapless system administrator's script suffered this very failure and it destroyed a large portion of an important production system. Don't let this happen to you! The problem with the script was that it did not check the exit status of the cd command before proceeding with the rm command. Checking the exit status There are several ways you can get and respond to the exit status of a program. First, you can examine the contents of the $? environment variable. $? will contain the exit status of the last command executed. You can see this work with the following: [me] $ true; echo $? 0 [me] $ false; echo $? 1 The true and false commands are programs that do nothing except return an exit status of zero and one, respectively. Using them, we can see how the $? environment variable contains the exit status of the previous program. So to check the exit status, we could write the script this way: # Check the exit status cd $some_directory if [ "$?" = "0" ]; then rm * else echo "Cannot change directory!" 1>&2 exit 1 fi In this version, we examine the exit status of the cd c
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us http://unix.stackexchange.com/questions/241178/how-can-i-get-this-script-to-error-exit-based-on-result-of-for-loop Unix & Linux Questions Tags Users Badges Unanswered Ask Question _ Unix & Linux Stack Exchange is http://unix.stackexchange.com/questions/82224/how-to-make-bash-abort-the-execution-of-a-script-on-syntax-error a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top How can I get this script to error exit based on result of for loop? up vote 4 down vote favorite 1 I exit code have a bash script which uses set -o errexit so that on error the entire script exits at the point of failure. The script runs a curl command which sometimes fails to retrieve the intended file - however when this occurs the script doesn't error exit. I have added a for loop to pause for a few seconds then retry the curl command use false at the bottom of the for loop to define a default non-zero exit status - if the curl command succeeds - the exit bash script loop breaks and the exit status of the last command should be zero. #! /bin/bash set -o errexit # ... for (( i=1; i<5; i++ )) do echo "attempt number: "$i curl -LSso ~/.vim/autoload/pathogen.vim https://tpo.pe/pathogen.vim if [ -f ~/.vim/autoload/pathogen.vim ] then echo "file has been retrieved by curl, so breaking now..." break; fi echo "curl'ed file doesn't yet exist, so now will wait 5 seconds and retry" sleep 5 # exit with non-zero status so main script will errexit false done # rest of script ..... The problem is when the curl command fails, the loop retries the command five times - if all attempts are unsuccessful the for loop finishes and the main script resumes - instead of triggering the errexit. How can I get the entire script to exit if this curl statement fails? bash shell-script share|improve this question edited Nov 6 '15 at 8:02 asked Nov 6 '15 at 7:10 the_velour_fog 2,4491122 add a comment| 4 Answers 4 active oldest votes up vote 3 down vote accepted Replace: done with: done || exit 1 This will cause the code to exit if the for loop exits with a non-zero exit code. As a point of trivia, the 1 in exit 1 is not needed. A plain exit command would exit with the exit status of the last executed command which would be false (code=1) if the download fails. If the download succeeds, the exit code of the loop is the exit code of the echo command. echo normally exits with code=0, signally success. In that case
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Unix & Linux Questions Tags Users Badges Unanswered Ask Question _ Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top How to make bash abort the execution of a script on syntax error? up vote 14 down vote favorite 5 To be on safe side, I'd like bash abort the execution of a script if it encounters a syntax error. To my surprise, I can't achieve this. (set -e is not enough.) Example: #!/bin/bash # Do exit on any error: set -e readonly a=(1 2) # A syntax error is here: if (( "${a[#]}" == 2 )); then echo ok else echo not ok fi echo status $? echo 'Bad: has not aborted execution on syntax error!' Result (bash-3.2.39 or bash-3.2.51): $ ./sh-on-syntax-err ./sh-on-syntax-err: line 10: #: syntax error: operand expected (error token is "#") status 1 Bad: has not aborted execution on syntax error! $ Well, we can't check $? after every statement to catch syntax errors. (I expected such safe behavior from a sensible programming language... perhaps this must be reported as a bug/wish to bash developers) More experiments if makes no difference. Removing if: #!/bin/bash set -e # exit on any error readonly a=(1 2) # A syntax error is here: (( "${a[#]}" == 2 )) echo status $? echo 'Bad: has not aborted execution on syntax error!' Result: $ ./sh-on-syntax-err ./sh-on-syntax-err: line 6: #: syntax error: operand expected (error token is "#") status 1 Bad: has not aborted execution on syntax error! $ Perhaps, it's related to exercise 2 from http://mywiki.wooledge.org/BashFAQ/105 and has something to do with (( )). But I find it still unreasonable to continue executing afte a syntax error. No, (( )) makes no difference! It behaves bad even without the arithmetic test! Just a simple, basic script: #!/bin/bash set -e # exit on any error readonly a=(1 2) # A syntax error is here: echo "${a[#]