use strict;
my $str = '// good case
#000
#123
#999
#AAA
#aaa
#abc
#FFF
#0000
#9999
#AAAA
#aaaa
#abcd
#FFFF
#ffff
#000000
#456789
#999999
#AAAAAA
#aaaaaa
#abcdef
#FFFFFF
#ffffff
#00000000
#12345678
#99999999
#AAAAAAAA
#aaaaaaaa
#abcdefcc
#FFFFFFFF
#ffffffff
#00123456
//bad case
##
#0
#1
#F
#f
#12
#AB
#ae
#aaaaa
#fffff
#aaaah
#aaaaaaa
#0000000
#ffffhij
#h000000
#aaaaaaai
#000k0123
#asdfasfa
';
my $regex = qr/(^#[0-9A-Fa-f]{6}$)|(^#[0-9A-Fa-f]{3,4}$)|(^#[0-9A-Fa-f]{8}$)/mp;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html