Howto use cron for scheduling tasks

[Styno]

Everyone using this router for more than the usual stuff will get to a point where one or more tasks need to be scheduled to run once in a while. Unix/Linux provides the cron daemon to do this job and you can use it on the WL-500g as well.

What you need:
-The full busybox (from the downloads section of this forum)
-An USB mass storage device like an USB pen or USB HDD

Preparing the cron daemon:
- The cron daemon needs a configuration file located in '/var/spool/cron/crontabs'. Create these directorys with 'mkdir'
- Run the cron daemon with the following command (I assume the full busybox is in the root of your USB device): '/tmp/harddisk/busybox crondtab -e'. This will start the cron daemon in the configuration mode.
- Add your daily tasks to the configuration file. Additional info can be found here: http://www.techtutorials.net/tutorials/unix/cron.shtml
- Now the file created by crontabs holds the configuration. The filename is the username who started crontabs (e.g. 'admin'). This file needs to be restored between reboots using the flashfs system. Add the configuration file to /usr/local/.files (e.g. 'echo /var/spooler/cron/crontabs/admin >> /usr/local.files').

Last step, running the daemon at each boot:
To make sure the cron daemon is running after each reboot we need to put it into the /usr/local/sbin/post-boot script. Add the following line: '/tmp/harddisk/busybox crond'.

Save the changes with the following commands: 'flashfs save' and 'flashfs commit' and reboot the router.

[Styno]

The above post describes the procedure for firmwares 1.8.x.x and higher. For 1.7.x.x replace '/tmp/harddisk' with '/mnt/usbfs'. That should do the trick.

[barsju]

Since 1.9.2.7-1 crond is included in FW so there is no need for full busybox.
To quickly summarize Styno's post:

mkdir -p /var/spool/cron/crontabs
crontab -e
#Edit crontab file. See tutorials on crontab and vi (text editor)
#Ex. Press "a" for append-mode. Enter cron-command ex "00 1 * * * reboot" 
#to reboot everyday at 1 am. Press "Esc", ":wq" and "Enter" to save and quit.
mkdir -p /usr/local/sbin
echo "/var/spool/cron/crontabs/admin" >> /usr/local/.files
if [ ! -f /usr/local/sbin/post-boot ] ; then
echo "#!/bin/sh" > /usr/local/sbin/post-boot
fi
echo "/usr/sbin/crond" >> /usr/local/sbin/post-boot
chmod +x /usr/local/sbin/post-boot
flashfs save
flashfs commit
#If not already enabled:
flashfs enable
reboot

Edit:Fixed typo: spooler
Edit2: Fixed typo2: crond instead of crontab.
Edit3: Added "#!/bin/sh" to psot-boot if not existing.

PS: These commands should only be run once. If they fail you need to edit .files and post-boot manually before you can try again..

[Elron]

hi,
thanks for summarize this.
ist this line ok ?

echo "/var/spooler/cron/crontabs/admin" >> /usr/local/.files

or should it be

echo "/var/spool/cron/crontabs/admin" >> /usr/local/.files

my problem is now that

crontab -l

shows

59 4 * * * killall -1 pppd

but at 4:59 nothing happend.

What is wrong?
Say if you need any more information.

thanks for help
Elron

[barsju]

Oh. Yeah your right it should be:

echo "/var/spool/cron/crontabs/admin" >> /usr/local/.files

I'll fix in original post!

59 4 * * * killall -1 pppd

How about:

59 16 * * * killall -1 pppd

Or are you an earlybird?

B.

[Elron]

i mean 4:59 am

i waited for more than 24 h but ther was only the normal 24h reconnect nothing at 16:59 or 4:59