[ILUG] shellscripts from crontab

[kevin lyda]

On Fri, Feb 02, 2001 at 11:12:36AM +0000, Donncha O Caoimh wrote:
> On a related note, has anyone any nice ideas about appending crontab
> entries to a user crontab file? I mean, how to do it unattended. Perhaps
> some manipulation of the EDITOR variable perhaps? Creating a new crontab
> is easy, appending is the problem which led me to use /etc/crontab in
> the first place..

this solution would work but it might fail if two processes are modifying
the crontab at once:

    crontab -l > crontab.bak
    ( cat crontab.bak ; echo '1 2 * * * /usr/local/bin/foo' ) | crontab -

alternatively set EDITOR to a shell script that appends the new entries
to $1 and exits.  this might be more complex but it's better since i think
crontab(1) sets a lock.

    #!/bin/sh
    echo '1 2 * * * /usr/local/bin/foo' >> $1

kevin

-- 
kevin at suberic.net        i...  i have a dream.  and that dream is:
fork()'ed on 37058400    use DIY::Tiler;
meatspace place: work    my($t) = new DIY::Tiler;
                         $t->tile(-room => "en-suite", -style => "stone");