If you are executing a Bash script in your terminal and need to stop it before it exits on its own, you can use the Ctrl + C combination on your keyboard.
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
, &&
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
.
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 $jar_file. Please recheck the variables 1>&2
exit 1 # terminate and indicate error
fi
...
If you want to be able to handle an error instead of blindly exiting, instead of using set -e
, use a trap
on the ERR
pseudo signal.
#!/bin/bash
f () {
errorCode=$? # 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
.
Here is the way to do it:
#!/bin/sh
abort()
{
echo >&2 '
***************
*** ABORTED ***
***************
'
echo "An error occurred. Exiting..." >&2
exit 1
}
trap 'abort' 0
set -e
# Add your script below....
# If an error occurs, the abort() function will be called.
#----------------------------------------------------------
# ===> Your script goes here
# Done!
trap : 0
echo >&2 '
************
*** DONE ***
************
'
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