Showing age of a file

quarryman

Is there any way to show the age of a file in the shell rather than the date it was modified/created/

some option with 'ls' maybe?

krinDar

quarryman wrote:

Is there any way to show the age of a file in the shell rather than the date it was modified/created/

I am not aware of any single utility to do it, but you can figure it out yourself.

#!/bin/bash 

if [ ! -f $1 ]
then
        echo "usage: $0 <file>"
        exit 1;
fi

# determine modification date in seconds since epoch
mt=$(stat -c %Y $1);

# determine the current time
ct=$(date "+%s")

dt=$(( ct - mt));

echo "$1 is $dt seconds old"

This works for me on SuSe 9.

Requires gnu core utilities - most recent Linux flavours should have it,

quarryman

looks good but what is '-c'?

I get 'invalid arguement".

krinDar

quarryman wrote:

looks good but what is '-c'?

I get 'invalid arguement".

It tells stat how to format the output. We are looking for the
modification time in seconds since epoch.

Read the man page for stat and see if it lets you define the
format. Also, what OS are you using ?

quarryman

here's a screen of my man stat page.

not sure which, i think its Red Hat.

krinDar

quarryman wrote:

here's a screen of my man stat page.

not sure which, i think its Red Hat.

to find out do the following

uname -a
cat /etc/issue

Having said that it looks like the version of stat you have does not
support the formatting option, you can change the script I attached
to the following, it might work, it is difficult to know considering we
don't know the OS yet:

#!/bin/bash 

if [ ! -f $1 ]
then
        echo "usage: $0 <file>"
        exit 1;
fi

# determine modification date in seconds since epoch
set -- $(stat -t $1);
mt=${13}

# determine the current time
ct=$(date "+%s")

dt=$(( ct - mt));

echo "$1 is $dt seconds old"

quarryman

that works perfect! thanks.

can you tell me what these lines do exactly so?

set -- $(stat -t $1);
mt=${13}

thanks again

krinDar

quarryman wrote:

that works perfect! thanks.

can you tell me what these lines do exactly so?

Can you tell me the OS ?

It makes it a lot easier to answer questions of this nature if you
include as much information as possible, such as the OS, some
examples etc.

set -- $(stat -t $1);
mt=${13}

Stat, as the manpage explained, displays information about the file specified.
Run it (without the -t argument) and you will see what it does. Parsing the
normal output of stat is awkward, -t makes it easier to parse, all the
information is on one line and is space separated.

The 'set --' part takes the output of the 'stat' command and puts it into
the positional parameters, so $1 is the first part of the output from
stat - the filename, $2 the second part - the sized ... and $13 is the
modified time in seconds since epoch.

quarryman

from uname -a i get:

Linux siexxxxx xxxxxxxxx SMP Tue Jan 27 00:35:25 PST 2004 i686 unknown

let me know if the xxx'd data is required.

The 'set --' part takes the output of the 'stat' command and puts it into
the positional parameters, so $1 is the first part of the output from
stat - the filename, $2 the second part - the sized ... and $13 is the
modified time in seconds since epoch.

ok so this is similar to awk then? i might try using that instead.

krinDar

quarryman wrote:

from uname -a i get:

What about the content of /etc/issue

ok so this is similar to awk then? i might try using that instead.

No. Not at all. 'set' is part of the shell. Awk is a totally different utility
that is much more powerful.