Exception Handling in Bash

Here’s a convenient pattern for anyone doing Bash scripting: Use a subshell with the Bash halt-on-failure feature enabled to execute a set of commands but break as soon as any one of them fails.

The above example will print only “foo” because the false command returns a non-zero error code which causes the subshell to exit.

For quick and simple scripts it’s easy to just enable the halt-on-failure feature at the beginning of the entire script, but for anything more advanced, you want to be able to “catch” the error and handle it in a more sophisticated way.

Another similar mechanism that Bash provides is a way to run a command or function when the script exits:

This is also a great way to make your Bash scripts more robust, but is best reserved for standard cleanup, like removing temporary files that may have been created.