shell_script_design_goals.md

Shell Script Design Goals

• Don't avoid bashisms unless you know bash will be unavailable
  • Use #!/bin/bash rather than #!/bin/sh
  • If you are going to try to avoid bash, you must test on a system that does not have bash
• Always include a shebang #!
• Handle errors
  • Use set -eu (errexit & nounset)
• Sould be idemponent if read via source
  • Use subshells to avoid leaking unintended variables into the parent scope
  • Only define variables and functions
  • Don't run functions or commands that modify the system or environment
• Namespace variables and functions
• Mark internal variables and functions
  • Beginning a variable or function with an underscore is a common indicator of internal functionality
  • Beginning a variable or function with an underscore does not enforce internal-only
• Related functionality should be placed in a single script and behave differently according to the name called
  • Having multiple symlinks to the same script is a convenient way to optionally avoid specifying functionality via argument