Bash Stop Execution On Error
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Bash Stop Execution Of Script
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Bash Pause Execution
programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Automatic exit from bash shell script on error up vote 276 down vote favorite 48 I've been writing some shell script powershell stop execution on error and I would find it useful if there was the ability to halt the execution of said shell script if any of the commands failed. See below for an example: #!/bin/bash cd some_dir ./configure --some-flags make make install So in this case if the script can't change to the indicated directory then it would certainly not want to do a ./configure afterwards if it fails. Now I'm well aware that I could have bash exit status variable an if check for each command (which I think is a hopeless solution), but is there a global setting to make the script exit if one of the commands fails? bash shell exit share|improve this question edited Mar 29 '15 at 23:26 asked May 20 '10 at 4:21 radman 5,57462242 I did have a quick look for duplicates and couldn't find any. –radman May 20 '10 at 4:22 1 answer goes to Adam for the detail regarding set -e (which is exactly wanted). Also thanks to a_m0d for the info on traps (though not 100% relevant). –radman May 20 '10 at 5:07 add a comment| 7 Answers 7 active oldest votes up vote 440 down vote accepted Use the set -e builtin: #!/bin/bash set -e # Any subsequent(*) commands which fail will cause the shell script to exit immediately Alternatively, you can pass -e on the command line: bash -e my_script.sh You can also disable this behavior with set +e. (*) Note: The shell does not exit if the command that fails is part of the command list immediately following a while or until keyword, part of the test in an if statement, part of a && or || list, or if the command's return value is being inverted via ! (from man bash) share|improve th
Bash Prompts About Writing Robust Bash Shell Scripts Many people hack together shell scripts quickly to do simple tasks, but these soon take on a life of their own. Unfortunately shell scripts are full of
Bash Exit On Error With Message
subtle effects which result in scripts failing in unusual ways. It's possible to bash exit on error code write scripts which minimise these problems. In this article, I explain several techniques for writing robust bash scripts. Use
Shell Script Error Handling
set -u How often have you written a script that broke because a variable wasn't set? I know I have, many times. chroot=$1 ... rm -rf $chroot/usr/share/doc If you ran the script http://stackoverflow.com/questions/2870992/automatic-exit-from-bash-shell-script-on-error above and accidentally forgot to give a parameter, you would have just deleted all of your system documentation rather than making a smaller chroot. So what can you do about it? Fortunately bash provides you with set -u, which will exit your script if you try to use an uninitialised variable. You can also use the slightly more readable set -o nounset. david% bash /tmp/shrink-chroot.sh $chroot= david% http://www.davidpashley.com/articles/writing-robust-shell-scripts/ bash -u /tmp/shrink-chroot.sh /tmp/shrink-chroot.sh: line 3: $1: unbound variable david% Use set -e Every script you write should include set -e at the top. This tells bash that it should exit the script if any statement returns a non-true return value. The benefit of using -e is that it prevents errors snowballing into serious issues when they could have been caught earlier. Again, for readability you may want to use set -o errexit. Using -e gives you error checking for free. If you forget to check something, bash will do it or you. Unfortunately it means you can't check $? as bash will never get to the checking code if it isn't zero. There are other constructs you could use: command if [ "$?"-ne 0]; then echo "command failed"; exit 1; fi could be replaced with command || { echo "command failed"; exit 1; } or if ! command; then echo "command failed"; exit 1; fi What if you have a command that returns non-zero or you are not interested in its return value? You can use command || true, or if you have a longer section of code, you can turn off the error checking,
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 http://unix.stackexchange.com/questions/82224/how-to-make-bash-abort-the-execution-of-a-script-on-syntax-error 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 _ https://ubuntuforums.org/showthread.php?t=1008259 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 on error 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 bash stop execution 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
Get Kubuntu Get Xubuntu Get Lubuntu Get UbuntuStudio Get Mythbuntu Get Edubuntu Get Ubuntu-GNOME Get UbuntuKylin Ubuntu Code of Conduct Ubuntu Wiki Community Wiki Other Support Launchpad Answers Ubuntu IRC Support AskUbuntu Official Documentation User Documentation Social Media Facebook Twitter Useful Links Distrowatch Bugs: Ubuntu PPAs: Ubuntu Web Upd8: Ubuntu OMG! Ubuntu Ubuntu Insights Planet Ubuntu Activity Page Please read before SSO login Advanced Search Forum The Ubuntu Forum Community Ubuntu Specialised Support Development & Programming Programming Talk [SOLVED] Make shell script exit as soon as a command in it returns an error? Having an Issue With Posting ? Do you want to help us debug the posting issues ? < is the place to report it, thanks ! Results 1 to 8 of 8 Thread: [SOLVED] Make shell script exit as soon as a command in it returns an error? Thread Tools Show Printable Version Subscribe to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode December 11th, 2008 #1 jasper.davidson View Profile View Forum Posts Private Message 5 Cups of Ubuntu Join Date Jul 2008 Beans 26 [SOLVED] Make shell script exit as soon as a command in it returns an error? I would like to make my shell script so that if any of the commands in it return an error, the script immmediately exits without executing the rest of the commands. What might be the best way of doing this? One way that seems to work is: Code: #!/bin/bash cmd1 || exit 1 cmd2 || exit 1 cmd3 || exit 1 etc. In other words, putting "|| exit 1" at the end of each executed command. Is there a better way I hope? Thanks in advance. Adv Reply December 11th, 2008 #2 dwhitney67 View Profile View Forum Posts Private Message Tolerant of Ubuntu Join Date Jun 2007 Location Maryland, US Beans 6,270 DistroKubuntu Re: Make s