PERL Script To Find How Many Seconds Back Was A File Updated

A lot of times in Unix, you would want to find out how many seconds (or minutes, or hours) back a particular file was updated. You would want to do it for several reasons - find out the last time some configuration file was changed, or may to track some update done by a different system, or anything that fancies your mind.

Though the script can be written as a Unix shell script, I found it a bit cumbersome. Moreover, the PERL solution was much more flexible, elegant and readable.

So, here is the PERL script that calculates the time period between the modified date of a file, and the system date.

#!/usr/bin/env perl
use File::stat;
# Declare variables
my $filename;
my $FILE_HANDLE;
my $file_stat;
my $current_time;
my $diff_seconds;
$filename = '/path/of/file/filename.ext';
# Open the file
open ($FILE_HANDLE, $filename)
or die "Can't open $filename!";
# Get the file status structure
$file_stat = stat($FILE_HANDLE);
# Get the current time
$current_time = time;
# Get the elapsed time in seconds
$diff_seconds = time - $file_stat->mtime;
# Do whatever you want with the $diff_seconds
print "\n$filename was modified $diff_seconds seconds back.\n";
# All done

Note:

• Instead of the $file_stat->mtime, you can use $file_stat->ctime to get the time from creation of the file.
• To get the elapsed time in minutes, divide $diff_seconds by 60. For hours, divide by 3600. And so on.