How do I get a file's last modified time in Perl?

Question

Suppose I have a filehandle $fh. I can check its existence with -e $fh or its file size with -s $fh or a slew of additional information about the file. How can I get its last modified time stamp?

Answer 1

Use the builtin stat function. Or more specifically:

my $modtime = (stat($fh))[9]

Answer 2

You could use stat() or the File::Stat module.

perldoc -f stat

Answer 3

You need the stat call, and the file name:

my $last_mod_time = (stat ($file))[9];

Perl also has a different version:

my $last_mod_time = -M $file;

but that value is relative to when the program started. This is useful for things like sorting, but you probably want the first version.

Answer 4

@array=stat($filehandle);

The modification time is stored in unix format in $array[9]

Or explicitly:

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

  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

The epoch was at 00:00 January 1, 1970 GMT.

More information on stat.

Answer 5

I think you're looking for the stat function (perldoc -f stat)

In particular, the 9th field (10th, index #9) of the returned list is the last modify time of the file in seconds since the epoch.

So:

my $last_modified = (stat($fh))[9];

Answer 6

You can use the built-in module File::stat (included as of Perl 5.004).

Calling stat($fh) returns an array with the following information about the file handle passed in (from the perlfunc man page for stat):

  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 since the epoch
  9 mtime    last modify time since the epoch
 10 ctime    inode change time (NOT creation time!) since the epoch
 11 blksize  preferred block size for file system I/O
 12 blocks   actual number of blocks allocated

The 9th element in this array will give you the last modified time since the epoch (00:00 January 1, 1970 GMT). From that you can determine the local time:

my $epoch_timestamp = (stat($fh))[9];
my $timestamp       = localtime($epoch_timestamp);

To avoid the magic number 9 needed in the previous example, additionally use Time::localtime, another built-in module (also included as of Perl 5.004). This requires some (arguably) more legible code:

use File::stat;
use Time::localtime;
my $timestamp = ctime(stat($fh)->mtime);

Answer 7

If you're just comparing two files to see which is newer then -C should work.

if (-C "file1.txt" > -C "file2.txt"){ { /* Update */ }

There's also -M but I don't think it's what you want. Luckily it's almost impossible to search for docs on these file operators via Google.