Exit a Script On Error

Question

I m building a Shell Script that has a if function like this one   if jarsigner -verbose -keystore  keyst -keystore  pass  jar file  kalias then     echo  jar file signed sucessfully else     echo ERROR  Failed to sign  jar file  Please recheck the variables fi        I want the execution of the script to finish after displaying the error message  How I can do this

User · Answer

exit 1 is all you need   The 1 is a return code  so you can change it if you want  say  1 to mean a successful run and -1 to mean a failure or something like that

User · Answer

Are you looking for exit   This is the best bash guide around  http   tldp org LDP abs html   In context   if jarsigner -verbose -keystore  keyst -keystore  pass  jar file  kalias then     echo  jar file signed sucessfully else     echo ERROR  Failed to sign  jar file  Please recheck the variables 1 gt  amp 2     exit 1   terminate and indicate error fi

User · Answer

Here is the way to do it      bin sh  abort         echo  gt  amp 2                       ABORTED                           echo  An error occurred  Exiting      gt  amp 2     exit 1    trap  abort  0  set -e    Add your script below       If an error occurs  the abort   function will be called   ----------------------------------------------------------       gt  Your script goes here   Done  trap   0  echo  gt  amp 2                    DONE

User · Answer

If you put set -e in a script  the script will terminate as soon as any command inside it fails  i e  as soon as any command returns a nonzero status   This doesn t let you write your own message  but often the failing command s own messages are enough   The advantage of this approach is that it s automatic  you don t run the risk of forgetting to deal with an error case   Commands whose status is tested by a conditional  such as if   amp  amp  or     do not terminate the script  otherwise the conditional would be pointless   An idiom for the occasional command whose failure doesn t matter is command-that-may-fail    true  You can also turn set -e off for a part of the script with set  e

User · Answer

If you want to be able to handle an error instead of blindly exiting  instead of using set -e  use a trap on the ERR pseudo signal      bin bash f          errorCode      save the exit code as the first thing done in the trap function     echo  error  errorCode      echo  the command executing at the time of the error was      echo   BASH COMMAND      echo  on line   BASH LINENO 0          do some error handling  cleanup  logging  notification        BASH COMMAND contains the command that was being executed at the time of the trap         BASH LINENO 0   contains the line number in the script of that command       exit the script or return to try again  etc      exit  errorCode    or use some other value or do return instead   trap f ERR   do some stuff false   returns 1 so it triggers the trap   maybe do some other stuff   Other traps can be set to handle other signals  including the usual Unix signals plus the other Bash pseudo signals RETURN and DEBUG

[bash] Exit a Script On Error

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