filter regexp: '?' not working?

[mobileink]

Hi,

I need to watch .*\.ml$ and .*\.mli$ files. I think regex `.*.ml.?$" ought to work, but it doesn't, so I need to add two filters. Should '?' work? (This is using the C API of libfswatch.)

Thanks

[direvus]

This works for me:

fswatch -E -i '\.mli?$' -e '.*' .

Note the -E to switch into "extended" regexp mode.

A general tip for writing regexps: putting .* at the start or end of a pattern doesn't change anything, unless you are using a function that specifically anchors at the beginning or end of a string, or only matches against the entire string.

For example, in Python, re.match() only matches at the beginning of a string, but re.search() matches anywhere in the string. Most of the time unless you're told otherwise, a regexp will match anywhere in the string. In fswatch, it definitely matches anywhere in the string.