use strict;
use warnings;
use POSIX qw(strftime);

print strftime("arident16_%b%e%Y_2358.zip\n", gmtime);

output:
arident16_Jul292009_2358.zip

##</code><code>##

### at the top of the file:
use POSIX qw(strftime);

### ...

### just before your foreach loop:

my $files_to_match = strftime("%b%e%Y_2358.zip", gmtime);

foreach $file (@list)
{
    # N.B. I am assuming $file contains the filename here. 

    # skip files that don't end with $files_to_match
    # N.B. could use regex here, not sure what's faster.
    next unless 
        substr($file, 0 - length($files_to_match)) 
        eq $files_to_match; 
    
    ### Then what you did already. I didn't check that.

}

### quit, etc...