Bash Script Abort On Error
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Bash Script Exit With Error Message
Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a shell script error handling community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Aborting a shell script if any command returns a non-zero value? up vote 239 down bash fail command vote favorite 71 I have a Bash shell script that invokes a number of commands. I would like to have the shell script automatically exit with a return value of 1 if any of the commands return a non-zero value. Is this possible without explicitly checking the result of each command? e.g. dosomething1 if [[ $? -ne 0 ]]; then exit 1 fi dosomething2 if [[ $? -ne 0 ]]; then
Bash Exit On Error With Message
exit 1 fi linux bash unix shell share|improve this question edited Sep 16 '12 at 11:01 Mat 135k20234273 asked May 4 '09 at 18:55 Jin Kim 4,602113460 2 In addition to set -e, also do set -u (or set -eu). -u puts an end to the idiotic, bug-hiding behavior that you can access any nonexistent variable and have a blank value produced with no diagnostics. –Kaz Feb 21 '14 at 1:36 add a comment| 8 Answers 8 active oldest votes up vote 414 down vote accepted Add this to the beginning of the script: set -e This will cause the shell to exit immediately if a simple command exits with a nonzero exit value. A simple command is any command not part of an if, while, or until test, or part of an && or || list. See the bash(1) man page on the "set" internal command for more details. I personally start almost all shell scripts with "set -e". It's really annoying to have a script stubbornly continue when something fails in the middle and breaks assumptions for the rest of the script. share|improve this answer edited May 4 '09 at 19:16 answered May 4 '09 at 19:00 Ville Laurikari 16.8k54449 30 That would work, but I
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Bash Catch Error
Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each http://stackoverflow.com/questions/821396/aborting-a-shell-script-if-any-command-returns-a-non-zero-value other. Join them; it only takes a minute: Sign up Stop on first error [duplicate] up vote 115 down vote favorite 28 Possible Duplicate: Automatic exit from bash shell script on error How can I have bash stop on the first command failure, without putting stuff like this all through my code? some_prog || exit 1 some_other_prog || exit http://stackoverflow.com/questions/3474526/stop-on-first-error 1 bash share|improve this question asked Aug 13 '10 at 6:45 Matt Joiner 41.2k43213382 marked as duplicate by martin clayton, Barmar, Toto, codesparkle, Emil Vikström Oct 13 '12 at 10:31 This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question. add a comment| 1 Answer 1 active oldest votes up vote 237 down vote accepted Maybe you want set -e: http://www.davidpashley.com/articles/writing-robust-shell-scripts.html#id2382181 share|improve this answer answered Aug 13 '10 at 6:50 Alok Singhal 48.8k1290125 31 Be aware of set -e gotchas: mywiki.wooledge.org/BashFAQ/105 –Kris Jun 9 '15 at 10:57 1 @Kris thanks for the link, very interesting. –Alok Singhal Jun 10 '15 at 3:45 2 @Kris, you just broke my heart. I thought -e was infallible. –Trenton Sep 30 '15 at 3:17 add a comment| Not the answer you're looking for? Browse other questions tagged bash or ask your own question. asked 6 years ago viewed 69578 times active 6 years ago Linked 276 Automatic exit f
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 http://linuxcommand.org/wss0150.php of your scripts. The difference between a good program and a poor one is often measured in terms of the program's robustness. That is, the program's ability to handle http://unix.stackexchange.com/questions/82224/how-to-make-bash-abort-the-execution-of-a-script-on-syntax-error situations in which something goes wrong. Exit status As you recall from previous lessons, every well-written program returns an exit status when it finishes. If a program finishes successfully, on error the exit status will 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 scripts return a meaningful exit status when they finish. I once had a Unix bash exit on 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 behavior. But what happens if the directory named in $some_directory doesn't exist? In that case, the cd command will fail and the script executes the rm command on the current working directory. Not the intended behavior! By the way, my hapless system administrator's script suffered this very failure and it destroyed a large portion of an important production system. Don't let this happen to you! The problem with the script was that it did not check the exit status of the cd command before proceeding with the rm command. Checking the exit status There are several ways you can get and respond to the exit
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Unix & Linux Questions Tags Users Badges Unanswered Ask Question _ Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top How to make bash abort the execution of a script on syntax error? up vote 14 down vote favorite 5 To be on safe side, I'd like bash abort the execution of a script if it encounters a syntax error. To my surprise, I can't achieve this. (set -e is not enough.) Example: #!/bin/bash # Do exit on any error: set -e readonly a=(1 2) # A syntax error is here: if (( "${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[#]}" echo status $? echo 'Bad: has not aborted execution on syntax error!' Result: $ ./sh-on-syntax-err ./sh-on-syntax