See the current Perl documentation for last.

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

last - exit a block prematurely

last LABEL


The last command is like the break statement in C (as used in loops); it immediately exits the loop in question. If the LABEL is omitted, the command refers to the innermost enclosing loop. The continue block, if any, is not executed:

    LINE: while (<STDIN>) {
        last LINE if /^$/;      # exit when done with header

See also continue for an illustration of how last, next, and redo work.