Exception to `set -e` in bash

Question

I have a bash script used to make my project. I have set -e in top of the script to break the execution when any component fails.

One of the commands would fail, but it is natural for it to fail. I would like the script to behave as such:

Run the script.
Reach and run the problematic command.
If it fails, don't break execution. Do this ONLY for this command.

Recommended reading: [BashFAQ/105](https://mywiki.wooledge.org/BashFAQ/105) — Benjamin W., Jan 03 '18 at 15:06

score 6 · Accepted Answer · answered Jan 03 '18 at 14:11

6

I suggest:

set +e
# your command which would fail
set -e

or

your_command_which_would_fail || true

answered Jan 03 '18 at 14:11

Cyrus

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Your first proposal would mean to switch `set -e` on after this command *even if it wasn't on before it* (i. e. in another context, after a patch, whatever). – Alfe Jan 03 '18 at 14:15
@Alfe: This is also possible with -e and +e: https://stackoverflow.com/a/48019999/3776858 – Cyrus Jan 03 '18 at 14:19
Yes, with more code. So I would not propose it for this usecase. – Alfe Jan 03 '18 at 14:22
Wow, thanks both @Alfe and @Cyrus for the prompt reply. I went with the `|| true` option. – solidak Jan 03 '18 at 15:01

score 2 · Answer 2 · answered Jan 03 '18 at 14:33

The flag set -e has a bunch of exemptions where it doesn't lead to an abort right away after an executed command failed (exitcode ≠ 0). Among these are the connections as @cyrus proposed (a || b and similar). See man bash for details; it's kind of hard to find, maybe this helps:

man bash | grep -B 20 -A 10000 'Exit.*immediately' | less

My proposal would be to put it in an if:

if command
then
    : "worked nicely"
else
    : "failed, but we don't want to abort"
fi

or @Cyrus's short version:

command || true  # do not abort in case of 'set -e'

Exception to `set -e` in bash

2 Answers2