Cron not displaying jobs

[clapclash]

Hi everyone! I'm running fedora 15, cron is running and I'm trying to execute a simple date command in a crontab that should run every minute but unfortunately it doesn't.
This is the output from /var/log/cron:
Jun 27 22:33:01 sonda /USR/SBIN/CROND[2834]: (sonda) CMD (date)

checking the user email i got this:
From sonda@sonda.localdomain Wed Jun 27 22:33:02 2012
Return-Path: <sonda@sonda.localdomain>
Received: from sonda.localdomain (localhost.localdomain [127.0.0.1])
by sonda.localdomain (8.14.5/8.14.5) with ESMTP id q5RLX2Mi002837
for <sonda@sonda.localdomain>; Wed, 27 Jun 2012 22:33:02 +0100
Received: (from sonda@localhost)
by sonda.localdomain (8.14.5/8.14.5/Submit) id q5RLX2Cc002835;
Wed, 27 Jun 2012 22:33:02 +0100
Date: Wed, 27 Jun 2012 22:33:02 +0100
Message-Id: <201206272133.q5RLX2Cc002835@sonda.localdomain>
From: sonda@sonda.localdomain (Cron Daemon)
To: sonda@sonda.localdomain
Subject: Cron <sonda@sonda> date
Content-Type: text/plain; charset=UTF-8
Auto-Submitted: auto-generated
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/home/sonda>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=sonda>
X-Cron-Env: <USER=sonda>

Wed Jun 27 22:33:01 BST 2012


Now the question is: why cron displays the date in a mail and not using a terminal???

[marko]

Now the question is: why cron displays the date in a mail and not using a terminal???

Do you mean you literally want a terminal window to appear each minute and show the current date command?

Would you post the crontab line here that you tried to run and state what you want to do?

[george_toolan]

Because cron doesn't have a terminal ;-)

Try

while true; do date; sleep 60s; done

[clapclash]

Thanks for the reply, I know cron doesn't have any terminal, that's why I tried to launch an xterm followed by date command but with no result.

[jpollard]

It also has no display.

Sometimes you can get around that with "xterm -display :0.0" but that doesn't always work as the actual display you may be using varies.

Right now (F16) for some reason the users logged in display is 1.0, but sometimes (usually right after a boot) it is 0.0.

It will also fail if you aren't logged in.

---------- Post added at 10:19 AM ---------- Previous post was at 10:14 AM ----------

BTW, something I also forgot to mention.

If the command you run in cron is "xterm -display :0.0 date" then the best you will get is a flicker.

The xterm terminal emulator terminates when the command it is using (the date) exits. So you won't really see anything.

[sea]

As an idea, you could redirect the output to a file, and open that instead?

[jpollard]

A thought.

If all you are trying to do is explore how cron operates, you could do something slightly different.

After logging in, start a terminal window, and use the "tty" command to identify it. It will show a path like "/dev/pts/2".

Then edit the cron entry and change the command to "date >/dev/pts/2"

Wait a bit and the date should start coming up every minute or so. Some delays can be expected, and sometimes missing due to:

1) too many cron jobs occuring at once (not usually, but does happen sometimes)
2) delayed due to large number starting at once.

Expected variations should be within 5 seconds though.

Oh - be sure to remove the cron job before you terminate the terminal window. You might get surprised the next time you open a window and start doing something else.

[clapclash]

jpollard thank u very much! Your solution is working and it's really interesting as well!!!