How to monitor certificate expiry date using a linux script

jefn · 04-26-2009, 08:29 AM

Hi,

I face a problem to compare time and date. I need to convert the format of the output of "date" command with the following default format:

Mon Apr 27 02:29:57 EST 2009

to the following Format:

Apr 27 02:29:57 2009 GMT

The purpose of this is to design a script to monitor if a certificate expires or not. The latest format "Apr 27 02:29:57 2009 GMT" is the date format of the certificate which I cannot compare with "date".

How can I compare if it is expired? can you help me please ?

Thanks all in advance,
Jef

choogendyk · 04-26-2009, 01:38 PM

Try checking out `man convdate`. Put both in the form of seconds since the epoch, and then do a simple numerical comparison.

Alternatively, mon (http://mon.wiki.kernel.org/index.php/Main_Page) has a monitor module that checks web certs for expiration. With terms like "mon" and "monitor", that can be wickedly difficult to google.

So, I have to remember "kernel.org" to even find them, and then follow links from there or ask on their mailing list. However, I particularly like mon for its simplicity -- http://blogs.umass.edu/choogend/2007...nitoring-tool/

Asy · 04-26-2009, 03:38 PM

look to man date and use the [+Format....]
in the format you can use %Mon for month etc.

jlinkels · 04-26-2009, 07:48 PM

Forget about comparing dates this way. Sooner or later it goes wrong because there is one character different or the time zone doesn't match.

Use:

Code:

date -d "Mon Apr 27 02:29:57 EST 2009" +%s

and

Code:

date -d "Apr 27 02:29:57 2009 GMT" +%s

To get the time difference (or equality), use this expression:

Code:

donald_pc:~$ diff=$(echo "$(date -d "Apr 27 02:29:57 2009 GMT" +%s) $(date -d "Mon Apr 27 02:29:57 EST 2009" +%s) - p" | dc)
donald_pc:~$ echo $diff
-18000

The time difference is in seconds and 0 if there is no time difference. Note that these expression currently do not take DST into account, because I don't have tz_dsttime set on my computer. Maybe you should check that yourself on your own computer.

jlinkels

jefn · 04-27-2009, 04:36 AM

Quote:

Originally Posted by choogendyk

Try checking out `man convdate`. Put both in the form of seconds since the epoch, and then do a simple numerical comparison.

Alternatively, mon (http://mon.wiki.kernel.org/index.php/Main_Page) has a monitor module that checks web certs for expiration. With terms like "mon" and "monitor", that can be wickedly difficult to google.

So, I have to remember "kernel.org" to even find them, and then follow links from there or ask on their mailing list. However, I particularly like mon for its simplicity -- http://blogs.umass.edu/choogend/2007...nitoring-tool/

Thanks mate

jefn · 04-27-2009, 04:36 AM

Quote:

Originally Posted by Asy

look to man date and use the [+Format....]
in the format you can use %Mon for month etc.

Thanks mate

jefn · 04-27-2009, 04:37 AM

Quote:

Originally Posted by jlinkels

Forget about comparing dates this way. Sooner or later it goes wrong because there is one character different or the time zone doesn't match.

Use:

Code:

date -d "Mon Apr 27 02:29:57 EST 2009" +%s

and

Code:

date -d "Apr 27 02:29:57 2009 GMT" +%s

To get the time difference (or equality), use this expression:

Code:

donald_pc:~$ diff=$(echo "$(date -d "Apr 27 02:29:57 2009 GMT" +%s) $(date -d "Mon Apr 27 02:29:57 EST 2009" +%s) - p" | dc)
donald_pc:~$ echo $diff
-18000

The time difference is in seconds and 0 if there is no time difference. Note that these expression currently do not take DST into account, because I don't have tz_dsttime set on my computer. Maybe you should check that yourself on your own computer.

jlinkels

I think this is what I am looking for.

Thanks alot mate,