crond

[Jeff Vian]

On Tue, 2005-01-04 at 20:04 -0500, Erik Hemdal wrote:
> >
> > I've written the following script (named checkconn)
> > to be executed every 5 minutes by crond:
> >
> >
> 
> . . .
> 
> >     `/sbin/adsl-stop`
> >     `/sbin/adsl-start`
> 
> . . .
> 
> > 0,10,20,30,40,50 * * * * /root/cron/checkconn
> > 5,15,25,35,45,55 * * * * /root/cron/checkconn
> >
> >
> > Well, if I execute checkconn from the command line,
> > it works as expected, while when checkconn is invoked
> > by crond, it doesn't work...
> >
> 
> 
> > Any idea?
> > j3d.
> >
> 
> Here are a few thoughts.  Anything in /sbin is likely to need root privilege
> to run.
> So make sure that you use root's crontab, or place the entries in
> /etc/crontab and specify
> that they run as user root.  Also, since cron uses a limited path, make
> certain that
> /root/cron is in the path (add a PATH= line to the crontab entry).  Try man
> 8 crontab (IIRC) for information
> on the crontab file format as opposed to the crontab command.
> 

1.  For Erik:
    His command uses the full path.  Thus the path comment above is
superfluous.

2.  for j3d.
    The script being called by cron should contain a shebang line as the
first line.  Does it?
it should look like "#! /bin/sh".  You can look at any of the scripts
in /etc/init.d to see what should be there. 

3.  For j3d:
    What is the purpose of stop/start the adsl connection every 5
minutes?  As I understand it you are simply verifying the connection is
intact.  It would make more sense to do a simple ping to some host on
the internet, and if that fails then do the stop/start.  Otherwise the
connection is good and you quit.
    A drawback to your approach is that the IP address may (and often
does) change when the adsl connection is re-established.  If you are
using it the IP change may kick you off, and with a long download that
can be a problem.