How-to crontab question

My question is how to specify the one-time execution of a shell script in crontab?

For example: If I wanted to schedule shell "Test.sh" for one-time execution on December 13 at 8:00AM would it be as follows?

00 08 13 12 6 /usr/datatools/dtbackups/Test.sh > /usr/u/sybase_12.5/logs/Test.log &

My concern is that this job will fire on all Saturdays in December. If that is the case, what character needs to be placed in the day-of-week field to prevent this job from executing any day other than Dec. 13th?

Thanks,

Alan

For one-time job submissions, you want to use the at command. See the at man page for correct syntax, but basically...

at <time>
<command>
CTRL+D

It can be as simple as...

$ at 1100
ls
^d
Job userid.234234.a will be run at Thu Dec 11 11:00:00 EST 2009.

That would be 1100 today, if today were the 11th of Dec.

$ at now + 2 weeks
ls
^d
Job userid.234234.a will be run at Thu Dec 25 10:37:23 EST 2009.

Two weeks from today, if today were Dec 11.

I really appreciate your advice.

Thanks,

Alan

Hi Alan,

yes you are right Alan ,If you want to get it done using crontab then use the following syntax. which ou have already mentioned.
there should not be any doubt that this will run on every saturday. because you have already specifed the date as 13th DEC so it wll run on this particular day only if it is saturday.

00 08 13 12 6 /usr/datatools/dtbackups/Test.sh > /usr/u/sybase_12.5/logs/Test.log &