Editing Regular Expressions

Regular expressions are used in [[Filename_Filters|filename filters]] as a way to filter files on either the client or server side.

The flavor of regular expressions used are [http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions POSIX extended regular expressions].

Note that by selecting "None of the following" as a [[Filename_Filters|file filter criteria type]], you can effectively select those files that ''do not'' match the specified criteria.

= Regular Expressions Match Anywhere In The Name =

Unless anchored to the beginning or the end of the file name, they will match if they occur anywhere inside the file name. See the '^' and '$' characters.

Thus, if your regular expression is 'x', then any filename that contains the letter x anywhere will match (beginning, middle, or end).

= All Non-Special Characters =

All characters not specified below will match exactly in the filename. Thus, the regular expression 'foo' will match "foobar", "barfoo", and "quxfoobaz".

= The '.' Character =

The '.' character matches any single character. Thus, 'd.t' matches both "dat" and "dot".

= The '*' Character =

The '*' character matches 0 or more of the preceding token. Thus, 'foo.*bar' matches both "fooquxbar" and "foobar". The regular expression 'ge*k' matches "gk", "gek", "geek", and "geeeeeeeeeeeeeeeek".

= The '?' Character =

The '?' character matches 0 or 1 of the preceding token. Thus, 'gee?k' matches "gek" and "geek", but not "gk" or "geeek".

= The '^' Character =

The '^' character matches the beginning of the filename. So, '^x' matches all file whose names begin with the letter 'x'.

= The '$' Character =

The '$' character matches the end of the filename. Thus, 'x$' matches all files whose names end with the letter 'x'.

= The '\' Character =

This character escapes the following token, so that it does not take on special meaning. For example, if you wanted to filter for files that begin with a period, then the regular expression '^\.' would accomplish that for you. If you had just specified '^.', you would have matched all files that began with any single character.