How to exit a shell script on error AND message the user?

Question

I have a /bin/foo shell script file.

If I simply use a set -e then it exits on error, but no commands running when it hits error, like sending a message to STDOUT or sending a mail.

The question: how to run a command if the shell script runs to an error?

SLES12, bash.

see unix.stackexchange.com/q/39623/330217
– Bodo
CommentedJun 7, 2019 at 17:12 — Bodo, CommentedJun 7, 2019 at 17:12

jesse_b · Accepted Answer · 2019-06-07 17:15:17Z

4

You can create a function to message your user and use trap to have it execute when the script exits in error:

#!/bin/bash set -e on_exit () { echo "This script has exited in error" } trap on_exit ERR echo 'yes' | grep "$1"

In use:

$ ./script.sh yes yes $ ./script.sh no This script has exited in error

answered Jun 7, 2019 at 17:15

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As if there wasn't a recent flurry of questions about set -e being completely unreliable.
– user313992
CommentedJun 7, 2019 at 20:02
@UncleBilly: I don't know what you're talking about but this Q/A has nothing to do with the reliability of set -e. That is working exactly how it should.
– jesse_b
CommentedJun 7, 2019 at 20:04
Is it? What if the error happens inside a func? Would your trap be called or not? Also, think through whether/why do you need set -e at all.
– user313992
CommentedJun 7, 2019 at 20:21
It absolutely is. It would work fine with a function as long as the function was built properly. set -e is not really needed though when trapping err.
– jesse_b
CommentedJun 7, 2019 at 20:23

LoLi · Accepted Answer · 2024-03-24 13:26:22Z

If you want it to work on old sh too (instead just on bash):

#!/bin/sh set -e trap 'test $? -gt 0 && echo "This script has exited in error" >&2' 0 echo 'yes' | grep "$1"

2 Answers 2