How can I compare file creation time to the current time in Perl?

Question

i want to compare the current time and file creation time in Perl but both are in different format. localtime is in this format:

22116291110813630

and file creation time is

Today, December 29, 2008, 2:38:37 PM

How do i compare which one is greater and their difference?

Answer 1

localtime returns a list of values in list context. See the localtime documentation or perlcheat. In your example, it looks like those all mushed together. In scalar context, it returns a formatted string like Mon Dec 29 03:16:33 2008. On most platforms, the file inode change time will be returned from stat as a number of seconds since some epoch. You should be able to directly compare that to the result of time() (not localtime()).

Answer 2

If you want to compare values, you might want to use the number you got from localtime in scalar context and the inode change time that you can get from stat:

               ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
                  $atime,$mtime,$ctime,$blksize,$blocks)
                      = stat($filename);

where:

                 0 dev      device number of filesystem
                 1 ino      inode number
                 2 mode     file mode  (type and permissions)
                 3 nlink    number of (hard) links to the file
                 4 uid      numeric user ID of file's owner
                 5 gid      numeric group ID of file's owner
                 6 rdev     the device identifier (special files only)
                 7 size     total size of file, in bytes
                 8 atime    last access time in seconds since the epoch
                 9 mtime    last modify time in seconds since the epoch
                10 ctime    inode change time in seconds since the epoch (*)
                11 blksize  preferred block size for file system I/O
                12 blocks   actual number of blocks allocated

So you want field 9:

$mtime = ( stat $filename )[9];
$current_time = time;

$diff = $current_time - $mtime;

Answer 3

It's even easier than using stat() and time()/localtime().

my $diff = -M $filename;

The -M operator returns the "age" of the file (in days since the start of the program). It's documented in perlop.