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Commands tagged crontab from sorted by
Terminal - Commands tagged crontab - 8 results
echo $[RANDOM % 100] # range 0-99
2013-05-25 19:02:00
User: anapsix
Functions: echo
-2

use it to stagger cronjob or to get a random number

increase the range by replacing 100 with your own max value

for user in $(getent passwd|cut -f1 -d:); do echo "### Crontabs for $user ####"; crontab -u $user -l; done
2012-07-11 13:06:17
User: harpo
Functions: crontab cut echo getent
Tags: crontab getent
0

added echo "### Crontabs for $user ####"; to make clear whose crontab is listed.

for user in $(cut -f1 -d: /etc/passwd); do echo "### Crontabs for $user ####"; crontab -u $user -l; done
2012-07-11 12:25:56
User: harpo
Functions: crontab cut echo
Tags: crontab
3

added echo "### Crontabs for $user ####"; to make clear whose crontab is listed.

10,30,50 * * * * ping -c1 -w3 192.168.0.14 >/dev/null
2012-02-06 14:54:15
User: bashrc
Functions: ping
2

Cleaner with a mailto assignment in crontab (if the command fails you get an email):

MAILTO=admin@example.com

10,30,50 * * * * ping -q -c1 -w3 192.168.0.14 >/dev/null

10,30,50 * * * * ping -q -c1 -w3 192.168.0.14 | grep '1 received' - || mail -ne -s'Host 192.168.0.14 not reachable' admin@example.com
2012-02-06 10:42:46
User: knoppix5
Functions: grep mail ping
-4

Every 20 minutes test if host with IP 192.168.0.14 is 'dead' or not reachable.

The line should be put in your crontab file.

10,30,50 * * * * ping -q -c1 -w3 192.168.0.14 | grep '1 received' - || env DISPLAY=:0 xeyes
2012-02-06 09:40:11
User: knoppix5
Functions: env grep ping
Tags: ping host crontab
-2

Every 20 minutes ping host with IP address 192.168.0.14. If it's not 'alive' or not reachable, then display something eye-catching (here xeyes) on the desktop.

Hint for newbies: edit crontab with

crontab -e
( di $TOFSCK -h ; /bin/umount $TOFSCK ; time /sbin/e2fsck -y -f -v $FSCKDEV ; /bin/mount $TOFSCK ) |& /bin/mail $MAILTO -s "$MAILSUB"
2010-10-24 00:35:23
User: px
Functions: time
1

This one-liner is for cron jobs that need to provide some basic information about a filesystem and the time it takes to complete the operation. You can swap out the di command for df or du if that's your thing. The |& redirections the stderr and stdout to the mail command.

How to configure the variables.

TOFSCK=/path/to/mount

FSCKDEV=/dev/path/device

or

FSCKDEV=`grep $TOFSCK /proc/mounts | cut -f1 -d" "`

MAILSUB="weekly file system check $TOFSCK "

gconftool-2 -t str -s /desktop/gnome/background/picture_filename "$(find ~/Wallpapers -type f | shuf -n1)"
2010-09-21 04:01:55
User: zed
2

Changes your desktop background image in gnome. Update the directory to wherever you keep your wallpapers. I like to create a sub-directory in my Wallpaper folder called "cycle" that I use to define the wallpapers I wish to loop in cron. ex:

gconftool-2 -t str -s /desktop/gnome/background/picture_filename "$(find ~/Wallpapers/cycle -type f | shuf -n1)"