topic File creation/modification time in Operating System - Linux

File creation/modification time

Nitin Kumar Gupta — Mon, 10 Mar 2008 10:46:26 GMT

I want to check a file name, whether it is created/modified within last x mins or not.

How to do it?

I must take into consideration about leap year, year changed etc.

Rgds
-NKG-

Re: File creation/modification time

Pete Randall — Mon, 10 Mar 2008 11:01:28 GMT

Use "touch" to create a reference file with the appropriate date/time value, then use the find command with the "-newer" option to compare if the files are more recent than your reference file.

Do a man on touch and a man on find for specifics.

Pete

Re: File creation/modification time

James R. Ferguson — Mon, 10 Mar 2008 11:02:35 GMT

Hi:

There is no such thing in UNIX as a "creation" timestamp. The last modification ('mtime') is coincidently a creation at the instance that a file is first created. Thereafter it is updated any time the file contents or offset change.

That said, you can use 'find' to look for files meeting your criteria. The '-mtime' argument is a 24-hour increment. The '-newer' argument used with a "reference file" and 'touch' allows measurement from a preset point.

Perl provides the easy way to compute a file age in units of seconds:

# perl -le 'print "OK" if -e $ARGV[0] && -M $ARGV[0] > (3600/86400)' file

...would print "OK" if the file (name) passed as an argument to the Perl script were older than 3600/86400 of a day or older than 1-hour. Granularity is in seconds so one-second would be 1/86400 of a day.

Regards!

...JRF...

Re: File creation/modification time

Hein van den Heuvel — Mon, 10 Mar 2008 11:08:46 GMT

Standard smarty pants line: Unix does not maintain a 'created time' for files.

Many ways to solve this
touch + find ... -newer is always handy.

I use perl for just about everything.
It has a -M file function returning the Modified age for a file in days

In a verbose example:

$ perl -le '$file = shift; $_ = ( 5/(24*60) < -M $file) ? "old" : "new"; print'