What's happening here? #1 (Perl backreferences)

Examples: 

    s/^([^ ]*) *([^ ]*)/$2 $1/;     # swap first two words

    if (/(.)\1/) {                  # find first doubled char
         print "'$1' is the first doubled character\n";
    }

    if (/Time: (..):(..):(..)/) {   # parse out time values
    $hours = $1;
    $minutes = $2;
    $seconds = $3;
    }

Note the difference between the $1 and the \1 in the first and second lines. The last if statement is evidently intended to handle input lines that contain a date of the form hh:mm:ss.