bash-scripting-guidelines.md

Bash scripting guidelines

Interpreter

For better portability be sure to specify the interpreter in this way:

#! /usr/bin/env bash

Set options

For prevent hidden bugs use set -euox pipefail as the first command when possible. For additional info, please see manpages

Variables

Variables local to the script must be in the lower case.

Using variable is allowed only wrapped in "${}". Example:

var=123
echo "${var}"

If you need to use "$@", always use quotation marks. Example:

lua test/test.lua "$@"

If the script is sensitive to the current directory, store it in the ROOT variable. Example:

ROOT="${BASH_SOURCE[0]}"
if([ -h "${ROOT}" ]) then
  while([ -h "${ROOT}" ]) do ROOT=`readlink "${ROOT}"`; done
fi
ROOT=$(cd `dirname "${ROOT}"` && pwd)

Wrapping other programs

If the script is a wrapper around another program and no postprocessing is needed after execution of that program, you should strive to replace the shell without creating additional processes, using exec. Execution of the wrapper script will be terminated after the exec call. Example:

exec /usr/bin/env "${LE_LUA_INTERPRETER}" "$@"