use strict;
use warnings;

##</code><code>##

my $input_file = "dump.vcd";

##</code><code>##

open INPUT, '<', "$input_file";

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

my $input_file = "noname1.pl";

open INPUT, '<', "$input_file";

while (my $efile = <INPUT>) {
    $efile =~ s/\$var\w \d+ ([!,\#,\",\$,\%,&]) (\w) \$end/\$var $1 $2/;
    print $efile;
}

close INPUT;
__DATA__
$var1 1 , x $end
$varx 2 ! _ $end
$vary 3 # aa $end

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

my $input_file = "noname1.pl";

open INPUT, '<', "$input_file";

while (my $efile = <INPUT>) {
    $efile =~ s/\$var\w \d+ ([!,\#,\",\$,\%,&]) (\w) \$end/\$var $1 $2/;
    print $efile;
}

close INPUT;
__DATA__
$var , x
$var ! _
$vary 3 # aa $end