lc

See the current Perl documentation for lc.

Here is our local, out-dated (pre-5.6) version:

lc - return lower-case version of a string

lc EXPR

lc

Returns an lowercased version of EXPR. This is the internal function implementing the \L escape in double-quoted strings. Respects current LC_CTYPE locale if use locale in force. See the perllocale manpage.

If EXPR is omitted, uses $_.