How to denote required and optional arguments on the command line

• <required_argument>
• [optional_argument]

Option-arguments are shown separated from their options by characters, except when the option-argument is enclosed in the '[' and ']' notation to indicate that it is optional.

https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap12.html

Note

Zsh does not expand the tilde (~) in single or double quotes.

initial tildes and equals signs are not expanded

http://zsh.sourceforge.net/Guide/zshguide05.html

Best practices

What is the recommended way to temporarily switch to a different directory?

• Using a parenthesized command aka subshell
  • e.g. (cd <directory> && ls)
• Using cd <directory> and cd -
• Using pushd <directory> and popd

Decision tree

1. If your command can be written as a one-liner, use a subshell..
2. If you switch to several different directories in a row, use pushd <directory> and popd.
3. Otherwise, use cd <directory> and cd -.