> cat 701529.pl
#!/usr/bin/env perl

use strict;
use warnings;

my $file = shift;
print "file : $file\n";
my $fname;
if ($file =~ m/(\w+)\..*/) {
    $fname = $1;
}
else {
    die "Bad filename\n";
}
print "fname : $fname\n";
>
> ./701529.pl ./myfile.txt
file : ./myfile.txt
fname : myfile
>