I have this on a daily cronjob to backup the commandlinefu.com database from NearlyFreeSpeech.net (awesome hosts by the way) to my local drive. Note that (on my Ubuntu system at least) you need to escape the % signs on the crontab.
Another function to stick into your .bashrc This spits out the time two minutes in the future, but already formatted for pasting into your crontab file for testing without any thought required on your part. Frequently things don't work the way you expect inside a crontab job, and you probably want to find out now that your $PATH is completely different inside of cron or other global variables aren't defined. So this will generate a date you can use for testing now, and then later you can change it to run at 5:37 am on a Sunday evening. Show Sample Output
this is helpful because dmesg is where i/o errors, etc are logged to... you will also be able to see when the system reboots or someone attaches a thumb drive, etc. don't forget to set yourself up in /etc/aliases to get roots email.
This is how I list the crontab for all the users on a given system that actually have a crontab. You could wrap it with a function block and place it in your .profile or .bashrc for quick access. There's prolly a simpler way to do this. Discuss. Show Sample Output
works well in crontab.
I find it ugly & sexy at the same time isn't it ?
put it in crontab to get an alert when / is over 89% utilization.
added echo "### Crontabs for $user ####"; to make clear whose crontab is listed.
Reports all local partitions having more than 90% usage. Just add it in a crontab and you'll get a mail when a disk is full. (sending mail to the root user must work for that) Show Sample Output
Every time this is run it will change your background picture. For added fun Add some DBUS magic: . $HOME/.dbus/session-bus/`cat /var/lib/dbus/machine-id`-0 export DBUS_SESSION_BUS_ADDRESS and a crontab entry: */5 * * * * above_command_in_script.sh >/dev/null 2>/dev/null now wallpaper changes every 5 mins
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
Commandline-fu often has little tricks that I always forget. By adding this to the root-cron (sudo crontab -e) I lean a new trick every day.
or replace "espeak" with "festival --tts" if you like festival better
when your buddy leaves his computer unlocked use "crontab" or "at" to play at some time that would be most embarassing (during his next sales presentation)
echo "fortune -o | espeak" | at now + 30 minutes
of course you can exclude the "-o" for non offensive fortunes, or if you don't have offensive fortunes installed
additionally use "find /etc/cron*" for cronscripts Show Sample Output
This is helpful for shell scripts, I use it in my custom php install script to schedule to delete the build files in 3 hours, as the php install script is completely automated and is made to run slow. Does require at, which some environments without crontab still do have. You can add as many commands to the at you want. Here's how I delete them in case the script gets killed. (trapped) atq |awk '{print $1}'|xargs -iJ atrm J &>/dev/null
You can view the man pages from section five by passing the section number as an argument to the man command Show Sample Output
Simple way to backup your LDAP entries: put this line on your crontab. The -n switch identifies the dbnum you want to backup (alternatively you can use -b suffix. Check man slapcat for your personal switches)
The "-u USER" is optional if root user is used
Old cron doesn't allow periods
This is flatcaps tweaked command to make it work on SLES 11.2
Can be installed in the root crontab if you want it to update your motd. If not on ubuntu you need to change /usr/share/cowsay/cows/* to the location of your cow files. Show Sample Output
I find it useful when I want to add another crontab entry and I need to specify the appropriate PATH. I give ''whichpath'' a list of programs that I use inside my script and it gives me the PATH I need to use for this script. ''whichpath'' uses associative array, therefore you should have Bash v4 in order to run it. See sample output. Show Sample Output
added echo "### Crontabs for $user ####"; to make clear whose crontab is listed.
I have used crontab to run the one-liner and also to run a script containing the one-liner. Neither works. Show Sample Output
this one works on user crontab
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