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Bash Script Check Error Status


Is my workplace warning for texting my boss's private phone at night justified? Verbatim copying and distribution of this entire article is permitted in any medium, provided this copyright notice is preserved. Apart from portability, what are the benefits over ksh/bash/zsh's ERR trap? –Gilles Jan 11 at 17:07 Probably the only benefit is composability, as you don't risk to overwrite another Browse other questions tagged command-line or ask your own question. navigate here

Browse other questions tagged bash exit or ask your own question. comments powered by Disqus Benjamin is a Systems Architect working in the financial services industry focused on platforms that require Continuous Availability. return exit code. - Do you get that? - You changed that requirement arbitrarily to just make up an argument. –Janis Jun 14 '15 at 8:27 | show 8 more comments Calls to cd are another good use case here, as running a script in the wrong directory if a call to cd fails could have really nasty effects: cd wherever ||

Shell Script Check Error Code

To add our own exit code to this script, we can simply use the exit command. Any script that is useful in some fashion will inevitably be either used in another script, or wrapped with a bash one liner. share|improve this answer answered Sep 18 '08 at 6:09 Allen 3,9601328 17 What does it do? eval '[ "$?" = 127 ] || exit '"$?" Which basically allows you to expand the initial value for $?

Related Posts Bash command existence Calculating with Bash Cron best practices This entry was posted in Bash and tagged commands, conditionals, exit values, grouped commands, return values, testing by Tom Ryder. Note that in cases like (false); …, the ERR trap is executed in the subshell, so it can't cause the parent to exit. For example, to determine whether a particular regular expression regex was present somewhere in a file options, we might apply grep(1) with its POSIX -q option to suppress output and just Bash Script Check If Root Not the answer you're looking for?

share|improve this answer answered Mar 8 '11 at 23:54 geirha 21.3k84653 add a comment| up vote 9 down vote $? Bash Script If Error Code command1; then share|improve this answer edited Sep 23 at 17:57 answered Jul 10 '15 at 18:37 dimo414 20.2k774118 2 Thanks for the if ! What do you think about that method? –skozin Jan 11 at 16:36 @sam.kozin I don't have time to review your answer in detail, it looks good on principle. Notice that we explicitly exit from the script at the end of trap command, otherwise the script will resume from the point that the signal was received.

A temporary variable is the standard and preferred way to get the effect you're looking for. Bash Script Check If Directory Exists add_to_passwd $user cp -a /etc/skel /home/$user chown $user /home/$user -R There could be problems if you ran out of diskspace or someone killed the process. share|improve this answer edited Jun 14 '15 at 5:34 answered Jun 14 '15 at 1:03 mikeserv 37k341109 add a comment| up vote 8 down vote There are various options to handle You can optionally set the $LOG_STEPS variable to a log file name if you want to log which commands fail.

  • variable so you would have something like: ls -al file.ext rc=$?; if [[ $rc != 0 ]]; then exit $rc; fi You need to be careful of piped commands since the
  • The benefit of using -e is that it prevents errors snowballing into serious issues when they could have been caught earlier.
  • With Bash scripts, if the exit code is not specified in the script itself the exit code used will be the exit code of the last command run.

Bash Script If Error Code

Join them; it only takes a minute: Sign up Exit Shell Script Based on Process Exit Code up vote 238 down vote favorite 76 I have a shell script that executes in (1) ... ;; (127) ... ;; (*) echo $? ;; esac with the special case asked in the question: command -p sudo ... Shell Script Check Error Code function directoryExists { cd $1 if [ $? = 0 ] then echo -e "${green}$1${NC}" else echo -e "${red}$1${NC}" fi } # EXE directoryExists "~/foobar" directoryExists "/www/html/drupal" The script works, but Bash Script Exit Status more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed

Using parameter expansion, it is possible to perform a number of useful string manipulations. http://onlinetvsoftware.net/bash-script/bash-script-error-log.php The second use, ${1:-"Unknown Error"} means that if parameter 1 ($1) is undefined, substitute the string "Unknown Error" in its place. Some people just put them around every variable out of habit. Does mean=mode imply a symmetric distribution? Bash Script Check If Command Exists

share|improve this answer edited Mar 7 '11 at 13:14 answered Mar 7 '11 at 12:06 Lekensteyn 85.6k34220292 That's nice ...can i hold the output error ??!! , because in Can Customs make me go back to return my electronic equipment or is it a scam? check_exit_status "$?" Arguably, this is "cheating", since it makes a copy of $? http://onlinetvsoftware.net/bash-script/bash-script-error-127.php Verbs of buttons on websites Can Customs make me go back to return my electronic equipment or is it a scam?

The next approach we can try is to use the if statement directly, since it evaluates the exit status of commands it is given. Bash Script Check For Arguments Aborting." 1>&2 exit 1 fi Here we check to see if the cd command is successful. It is also important that your scripts return a meaningful exit status when they finish.

do_something $retval if [ $retval -ne 0 ]; then echo "Return code was not zero but $retval" fi For possible comparison operators, see man test.

They use the system functions from /etc/init.d/functions to print green [ OK ] and red [FAILED] status indicators. There are several things you can do to prevent errors in these situations. For example, if we were using the --max-delete option for rsync(1), we could check a call's return value to see whether rsync(1) hit the threshold for deleted file count and write Bash Script Check File Size The problem with temporary variables is that they could shadow other variables, and to avoid that you must use long names, which is not good for code readability.

COMMAND_LAST # Will exit with status of last command. fi for most cases, it's easier to use the && construct to chain commands that need to depend on each other. To explain how they work, I will quote from the bash man page: "The control operators && and || denote AND lists and OR lists, respectively. weblink share|improve this answer edited Jun 13 '15 at 17:05 eadmaster 351414 answered Jun 13 '15 at 14:34 llua 3,582716 1 Valid for this particular example, but only usable if there

execute a comand, 2. That's what is meant by i want to exit only if the first command is found (exit code != 127) and is a specified return for command when the command it I'd love to read a man page on this style of step/try/next logging –ThorSummoner Apr 27 '15 at 18:00 These shell functions seem to be unavailable on Ubuntu? Thanks for the review! =) –skozin Jan 11 at 17:20 @sam.kozin I forgot to write in my previous comment: you may want to post this on Code Review and

shell-script variable return-status share|improve this question edited Jul 15 '15 at 4:28 Evgeny Vereshchagin 1,8522721 asked Jun 13 '15 at 13:35 eadmaster 351414 No, but you can just do This is Bash's way of giving functions a "return value." [1]

Following the execution of a pipe, a $? gives the exit status of trap 'err=$?; echo >&2 "Exiting on error $err"; exit $err' ERR. If not, why?

Only then does rm get executed; otherwise an error message is output and the program exits with a code of 1, indicating that an error has occurred. share|improve this answer edited Jan 11 at 16:49 answered Jan 11 at 16:33 skozin 1336 add a comment| up vote 0 down vote You don't say what exactly you mean by The difference between a good program and a poor one is often measured in terms of the program's robustness. The two lines change the working directory to the name contained in $some_directory and delete the files in that directory.

share|improve this answer answered Jun 14 '15 at 0:48 David Z 456310 @mikeserv I'm not sure I understand - are you talking about manually assigning to $? inverts the exit status returned. As a previous poster noted, "set -e" will cause bash to exit with an error on any simple command. "set -o pipefail" will cause bash to exit with an error on