The regular expression most simply means that if the string stored in $data contains only 0 or more whitespace characters (between the start of a line and the end of the line) then do this. Else do that. This will match blank lines and lines that contain only whitespace.

As mentioned you should read perlre (link found above).

In reply to Re: Explaining a Regular Expression by zek152
in thread Explaining a Regular Expression by Anonymous Monk

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