Hi Derek,

Sorry to be pedantic, but the file matching expressions used by find and ls are not strictly “regularly expressions” – they are wildcards.
See the wikipedia entry at

http://en.wikipedia.org/wiki/Regular_expression

Last para, before the contents…

“Many modern computing systems provide wildcard characters in matching filenames from a file system. This is a core capability of many command-line shells and is also known as globbing. Wildcards differ from regular expressions in generally only expressing very limited forms of alternatives.”

In fact Regex are far far more powerful, and I often run find like

find . -type f | grep ‘.[ch]$’

which would do in a regex what find does by globbing. In this case the globbing is a lot easier, but

find . type f | grep -i “ansi”

would find that file I’m sure I had about ANSI command strings but couldn’t remember if I’d capitalised ANSI or not – it outputs any filename with “ansi” (in any case) in the name.

In fact GNU find has the options ‘-regex’ and ‘-iregex’ for actually doing regex matching on filenames (-iregex is the case insensitive version).
But busybox’s find doesn’t have this, or earlier BSD versions.

cheers
Jim