> perl -w tmp.pl
Possible unintended interpolation of @gmail in string at tmp.pl line 5.
Name "main::gmail" used only once: possible typo at tmp.pl line 5.
Terminating on signal SIGINT(2)

##</code><code>##

> type tmp.pl
#!/usr/bin/perl
use strict;

while (<>) {                   # take one input line at a time
    chomp;
    if (/(dmathis@gmail.\w+)/) {
        print "Matched: |$`<$&>$'|\n";  # the special match vars
    } else {
        print "No match: |$_|\n";
    }
}

> perl -w tmp.pl
Possible unintended interpolation of @gmail in string at tmp.pl line 6.
Global symbol "@gmail" requires explicit package name at tmp.pl line 6.
Execution of tmp.pl aborted due to compilation errors.

##</code><code>##

...
    if (/(dmathis\@gmail.\w+)/) {
...