# extremely brief regex overview

Regexes are powerful.  Gitolite uses that power as much as it can.  If you
can't handle that power, hire someone who can and become a manager.

That said, here's a very quick overview of the highlights.

`^` and `$` are called "anchors".  They anchor the match to the beginning and
end of the string respectively.

    ^foo    matches any string starting with 'foo'
    foo$    matches any string ending with 'foo'
    ^foo$   matches exact string 'foo'.

To be precise, the last one is "any string starting and ending with *the same*
'foo'".  "foofoo" does not match.

`[0-9]` is an example of a character class; it matches any single digit.
`[a-z]` matches any lower case alpha, and `[0-9a-f]` is the range of hex
characters.  You should now guess what `[a-zA-Z0-9_]` does.

`.` (the period) is special -- it matches any character.  If you want to match
an actual period, you need to say `\.`.

`*`, `?`, and `+` are quantifiers.  They apply to the previous token.  `a*`
means "zero or more 'a' characters".  Similarly `a+` means "one or more", and
`a?` means "zero or one".

As a result, `.*` means "any number (including zero) of any character".

The previous token need not be a single character; you can use parens to make
it longer.  `(foo)+` matches one or more "foo", (like "foo", "foofoo",
"foofoofoo", etc.)