hi, i am in need to schedule the execution of program once at particular time, as it is done in linux with help of "crontab". but how to do the same in arm board? is crontab available in arm? plz help me out thanks in advance!!!!!
chron is a Linux feature and available where ever Linux runs.
thanks Detour for replay but, as i said i need it for FriendlyARM .. i don't found it any where.
look at /usr/sbin for crond. You need a crontab in /etc, and start crond in your init file.
hi, i have seen crond in /usr/sbin . but there is no crontab in /etc. i need help how to implement in friendly arm.
If you type crontab -l on the prompt and nothing happens then you have to enable it in kernelconfig and re-compile. Under Busybox -> Miscellaneous Utilities look for crond and maybe you also need Busybox crontab Also, not much point starting another thread with the same name. The first post worked well.
Dear All,
Please explain me the procedure how to implement crontab job on
friendly arm with detailed explanation and sample code also.
I doubt if anyone is going to respond with a detailed procedure when there are hundreds of them floating around the net. Sample code: * * * * * /home/run-this-script.sh every minute the script will run. Best to do a bit of reading and then come with specific questions.
ram, Carefully re-reading your post AND the one before I don't see any /etc/crontab entry in my working system. If you do crontab -e you will be presented with your default editor and then you can put your job in that file as shown in the above post.
hi ,
when i do crontab -e it is saying that there is no file or
directory in /var/spool/cron/crontabs,
so i have created directories in var( mkdir spool ,mkdir
spool/cron,mkdir spool/cron/crontabs ) and i have run service saying crond
start in commmand prompt then service is executed, but when the system is
rebooted or shutdown then created directories are deleted, as var is mount
directory.
what is way overcome this problem.
thanks in advance.
You have to create your cron job as suggested above. Which kernel are you running? My /var and sub-directories are "permanently there". If you are using the FriendlyArm rootfs what does it say in /etc/rcS about your /var directory? Are you using an SD card or NFS or NAND? If SD card did you do a sync before shutting the machine down?
Thanks for ur reply
we are using linux-2.6.36.2 kernel mini 2440 friendly arm , we are
using Friendly arm rootfs where /etc/init.d/rcS having /var and its sub
directories are created, and we are using NAND .
I think I need to re-configure the kernel image for /var and its
sub-directories what are things to add for this /var/spool/cron-- is there
any alternate way to sort out this problem, is change in busybox work for
this.
Show the contents of /etc/init.d/rcS. The one I am looking at does not create /var Also, be aware the /etc is bound to /tmp which means any change to this file is not persistent. Whether or not this is your problem, I don't know.
/etc/init.d/rcS. contains
#! /bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:
runlevel=S
prevlevel=N
umask 022
export PATH runlevel prevlevel
#
# Trap CTRL-C &c only in this shell so we can interrupt subprocesses.
#
trap ":" INT QUIT TSTP
/bin/hostname FriendlyARM
/bin/mount -n -t sysfs none /sys
/bin/mount -n -t usbfs none /proc/bus/usb
/bin/mount -t ramfs none /dev
echo /sbin/mdev > /proc/sys/kernel/hotplug
/sbin/mdev -s
/bin/hotplug
# mounting file system specified in /etc/fstab
mkdir -p /dev/pts
mkdir -p /dev/shm
/bin/mount -n -t devpts none /dev/pts -o mode=0622
#! /bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin:
runlevel=S
prevlevel=N
umask 022
export PATH runlevel prevlevel
#
# Trap CTRL-C &c only in this shell so we can interrupt subprocesses.
#
trap ":" INT QUIT TSTP
/bin/hostname FriendlyARM
/bin/mount -n -t proc none /proc
/bin/mount -n -t sysfs none /sys
/bin/mount -n -t usbfs none /proc/bus/usb
/bin/mount -t ramfs none /dev
echo /sbin/mdev > /proc/sys/kernel/hotplug
/sbin/mdev -s
/bin/hotplug
# mounting file system specified in /etc/fstab
mkdir -p /dev/pts
mkdir -p /dev/shm
/bin/mount -n -t devpts none /dev/pts -o mode=0622
/bin/mount -n -t tmpfs tmpfs /dev/shm
have a look of this RCS file
Could you tell me where in this file /var is being created? > we are using Friendly arm rootfs where /etc/init.d/rcS having /var and > its subdirectories are created That file looks corrupted to me. Why the repetition? I have a rcS from 2.6.29.4 that looks something like that. Are you sure there is not a line like this: /bin/mount -n -t ramfs none /var I think that means /var and its subdirectories disappear when mini2440 is turned off. Would the solution be just: mkdir -p /var (as well)
hi , As u said i have created the directories for var/spool/cron/crontabs and executed the cronjobs. And I had added a job in /etc/crontab file but that is not executing . thanks in advance
Well, the only way I am going to be able to help is to see your real rcS file.
Dear Sir,
When ever i am adding cronjob in /etc/crontab, it is not executing.
can u help me how to achieve this with sample code.
Thanks In advance
Show us the contents of your cron job.
hi , This is etc/crontab file where 'wire' is job to be executed but for every 1 minute wire is not executing ... SHELL=/bin/bash PATH=/sbin:/bin:/usr/sbin:/usr/bin MAILTO=root # For details see man 4 crontabs # Example of job definition: # .---------------- minute (0 - 59) # | .------------- hour (0 - 23) # | | .---------- day of month (1 - 31) # | | | .------- month (1 - 12) OR jan,feb,mar,apr ... # | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,f # | | | | | # * * * * * user-name command to be executed */1 * * * * root /home/wire
What do you see when you: crontab -l Also, what is wire? An application, C file, .sh file? What is its file permissions? Can you run the file like this ./wire?
./wire no question mark
putting root in my crontabs stopped them executing. Try: * * * * * /home/wire You are root on the mini2440 I also some problems using */1 instead of * I think they are suppose to mean the same thing but Busybox crontab doesn't seem to think so. If there are any warning messages about a failed cron job I don't know where to look for them.
Evidently: "Cron-related messages, including success and failure, are logged to /var/log/cron". I made that directory but no messages appear in it even when the jobs don't execute.
hi, when i type crontab -l nothing it is showing about the job. "wire"is an executable of application in 'c'. i can run ./wire.
Well, then you haven't got any cron jobs. Did you invoke the command crontab -e and then add this text * * * * * /home/wire and save it and wait a few minutes? Which editor are you using on the target? And where are you saving your cron jobs to?
Dear Sir,
Adding job after typing crontab -e is worked on friendly arm for
me which is user level cronjob. But adding cronjob to /etc/crontab which is
system level cronjob is not working on friendly arm. PLease help me in this
aspect.
Thanks In Advance.
We seem to have come full-circle here. Have you read my comments to rajkumar? Show me the full listing of your rcS file.
hi, this is my rcS file where i have added cronjob. #! /bin/sh PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin: runlevel=S prevlevel=N umask 022 export PATH runlevel prevlevel # # Trap CTRL-C &c only in this shell so we can interrupt subprocesses. # trap ":" INT QUIT TSTP /bin/hostname FriendlyARM /bin/mount -n -t proc none /proc /bin/mount -n -t sysfs none /sys /bin/mount -n -t usbfs none /proc/bus/usb /bin/mount -t ramfs none /dev echo /sbin/mdev > /proc/sys/kernel/hotplug /sbin/mdev -s /bin/hotplug # mounting file system specified in /etc/fstab mkdir -p /dev/pts mkdir -p /dev/shm /bin/mount -n -t devpts none /dev/pts -o mode=0622 /bin/mount -n -t tmpfs tmpfs /dev/shm /bin/mount -n -t ramfs none /tmp /bin/mount -n -t ramfs none /var mkdir -p /var/empty mkdir -p /var/log mkdir -p /var/lock mkdir -p /var/run mkdir -p /var/tmp mkdir -p /var/spool mkdir -p /var/spool/cron mkdir -p /var/spool/cron/crontabs cp /task /var/spool/cron/crontabs/root crond start /sbin/hwclock -s syslogd /etc/rc.d/init.d/netd start echo " " > /dev/tty1 echo "Starting networking..." > /dev/tty1 sleep 1 /etc/rc.d/init.d/httpd start echo " " > /dev/tty1 echo "Starting web server..." > /dev/tty1 sleep 1 /etc/rc.d/init.d/leds start echo " " > /dev/tty1 echo "Starting leds service..." > /dev/tty1 echo " " sleep 1 /sbin/ifconfig lo 127.0.0.1 /etc/init.d/ifconfig-eth0 /bin/qtopia & echo " " > /dev/tty1 echo "Starting Qtopia, please waiting..." > /dev/tty1 /home/StartupARM
So, your cron job is being put in cp /task /var/spool/cron/crontabs/root But you said, > But adding cronjob to /etc/crontab which is > system level cronjob is not working on friendly arm. Where does this "task" come from?
I thought your cron job was calling wire. Is task a script that runs wire? So, from root can you run: ./task and get the expected behaviour? Good night.
Dear Sir,
When ever i am adding cronjob in /etc/crontab, it is not executing
on friendlyarm.
can u help me how to achieve this with sample code.
Can anybody help me.
Thanks In advance
[Solved]
1. create 'spool/cron/crontabs' in yaffs2 partition, eg. /home/
2. make soft link to '/var', eg. ln -s /home/spool /var/
3. crontab -e, ...
4. modify /etc/init.d/rcS, add follow lines:
# start crond
ln -s /home/spool /var/
/usr/sbin/crond
Hello, i am insert this commanf in rcS file /bin/mount -n -t sysfs none /sys show this signal mount: mounting none on /sys failed: Device or resource busy