Writing BASH Scripts

• Starting scripts
  • Set

This document collects basic syntax and best practices for writing BASH scripts.

Starting scripts

It is good practice to start BASH scripts with the following lines:

#!/bin/bash

set -euo pipefail

Set

The command set allows you to change shell options. The most useful flags are:

-e

Stop execution when an error is encountered. You can “catch” an error to prevent the shell from exiting by appending || true after a failing command.

-o pipefail

Catch errors in pipes. Return zero exit status only if all commands in a pipeline succeed.

-u

Error out when shell encounters undefined variables by their values.

-x

Debug mode. Prints every line and output, substituting variables

-f

Disable file globbing.