See the Search and replace functions. When you include parenthesis ( ) in a matched string, the matching text in the parenthesis may subsequently be referenced via variables $1, $2, $3, ... for each left parenthesis encountered. These matches can also be assigned as sequential values of an array.
#!/usr/local/bin/perl -w
$s = 'There is 1 date 10/25/95 in here somewhere.';
print "\$s=$s\n";
$s =~ /(\d{1,2})\/(\d{1,2})\/(\d{2,4})/;
print "Trick 1: \$1=$1, \$2=$2, \$3=$3,\n",
" \$\`=",$`," \$\'=",$',"\n";
($mo, $day, $year) =
( $s =~ /(\d{1,2})\/(\d{1,2})\/(\d{2,4})/ );
print "Trick 2: \$mo=$mo, \$day=$day, \$year=$year.\n";
($wholedate,$mo, $day, $year) =
( $s =~ /((\d{1,2})\/(\d{1,2})\/(\d{2,4}))/ );
print "Trick 3: \$wholedate=$wholedate, \$mo=$mo, ",
"\$day=$day, \$year=$year.\n";
$s=There is 1 date 10/25/95 in here somewhere.
Trick 1: $1=10, $2=25, $3=95,
$`=There is 1 date $'= in here somewhere.
Trick 2: $mo=10, $day=25, $year=95.
Trick 3: $wholedate=10/25/95, $mo=10, $day=25, $year=95.
$s=Beware of <STRONG>greedy</strong> regular expressions.
Try 1: $m=STRONG>greedy</strong
Try 2: $m=STRONG
Parsing
