When you never had problems with running/debugging a bash script, you might wonder what I am talking about.
Instead of introducing the possible problems, and then the way to counter them, let’s start with the solution.
All your bash scripts should probably start with…
#!/usr/bin/env bash
… wait… it goes on…
set -euxo pipefail
Wat?
Ok, let’s go through the options, one by one.
set -e
This makes a bash script to stop on error immediately, and exit.
Sounds like this should be the default,
and that is the way it is in Python,
but well,
in bash you need to activate this error mode,
otherwise the bash script just continues with the next line and you will possibly receive something you did not expect!
set -u
This makes the bash script error on uninitialized variables!
If you do not set this,
echo hello $name just gives hello - which you probably do not want.
set -o pipefail
This makes bash fail when any of the commands in a pipe fail, not only when the last one fails.
set -x
This makes bash print the commands before executing them, making debugging much, much easier.
You can also specify -x when executing the command like …
❯ bash -x -c "echo hi"
+ echo hi
hi
thanks
Once more, thanks to Anthony Sottile, from whom I learned this in his excellent video.