Perl time Vs Unix date output inconsistency
I assume you're talking about the time difference rather than the format difference, since your Perl code doesn't even attempt to replicate that format.
Use localtime instead of gmtime. The date command uses your local time by default. Notice that it says "EST", but gmtime returns UTC, a 5 hour difference.
You should also consider using a module to handle the date formatting. But that won't prevent confusion between local time and UTC.
Time::Piece has been included with Perl for almost seven years and will make your time and date code far easier.
use Time::Piece;my $then = gmtime(915149280);print $then->strftime('%d-%m-%Y %H:%M:%S %a'); # produces 01-01-1999 00:08:00 Fri
You can make this considerably easier by using strftime from the POSIX module.
perl -MPOSIX=strftime -le 'print strftime "%a %b %d %T %Y",localtime(915149280)'Thu Dec 31 16:08:00 1998
The POSIX module has been a core module since 1994. By using an explicit import list, you avoid loading some 500+ symbols that you don't require.