Question

my $pat = '^x.*d$';

my $dir = '/etc/inet.d';

if ( $dir =~ /$pat/xmsg ) { 

print "found ";

}

how to make it sucess

Answer 1

You can use YAPE::Regex::Explain to help you understand regular expressions:

use strict;
use warnings;

use YAPE::Regex::Explain;
my $re = qr/^x.*d$/xms;
print YAPE::Regex::Explain->new($re)->explain();

__END__

The regular expression:

(?msx-i:^x.*d$)

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?msx-i:                 group, but do not capture (with ^ and $
                         matching start and end of line) (with .
                         matching \n) (disregarding whitespace and
                         comments) (case-sensitive):
----------------------------------------------------------------------
  ^                        the beginning of a "line"
----------------------------------------------------------------------
  x                        'x'
----------------------------------------------------------------------
  .*                       any character (0 or more times (matching
                           the most amount possible))
----------------------------------------------------------------------
  d                        'd'
----------------------------------------------------------------------
  $                        before an optional \n, and the end of a
                           "line"
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

Also, you should not need the g modifier in this case. The documentation has plenty of information about regexes: perlre