Short PWD in BASH Prompts

It’s not uncommon to have inordinately deep directory hierarchy on your computer, especially if you’re like me and you like to give significant names to your directory. For example, if you’re using a 80×25 terminal, the location /home/steven/download/Album Photo/2009/06 jui/20-22/21-008-St-Georges-de-la-Malbaie will cause your shell prompt to wrap around the shell window quite messily. Of course, you could show only the last directory’s name, say 21-008-St-Georges-de-la-Malbaie to continue with my previous example, but that’s a bit terse, especially if you end up on a directory whose name is unexpectedly short.

The correct solution, may be, is to arrange the prompt to show adaptively long parts of the current working directory up to a given limit, and abstract parts of the path using, say, ..., and make sure the result is legible. For example, /home/steven/download/Album Photo/2009/06 jui/20-22/21-008-St-Georges-de-la-Malbaie, using a maximum prompt length of 50 would get shortened to .../06 jui/20-22/21-008-St-Georges-de-la-Malbaie, which is already much shorter yet retained its legibility and meaning.

Suggested Reading: Beginning Portable Shell Scripting

Peter Seebach — Beginning Portable Shell Scripting — Apress, 2008, 352 pp. ISBN 978-1-4302-1043-6

(buy at Amazon.com)

This book, like Bash Cookbook: Solutions and Examples for Bash Users isn’t overly technical. It focuses on one particular aspect of shell scripting, portability. While no one really expects a bash script to be excuted using a different shell, such as zsh, for example, Seebach shows us that there are ways to ensure that the scripts behave reasonnably well when executed in different environments and by different shells. Seebach presents various shell constructs and discusses their portability, giving numerous examples.