Commands using crontab sorted by votes

Commands using crontab (11)

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send kernel log (dmesg) notifications to root via cron

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 sample output - yours may be different.
6

(crontab -l; echo '* * * * * dmesg -c'; ) | crontab -

grokskookum · 2009-09-30 18:13:38 3
print crontab entries for all the users that actually have a crontab

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
This is sample output - yours may be different.
```
--- crontab for user_one ---
0  16 * * * /bin/foo >>/var/log/foo.log 2>&1
42 10 * * * /bin/bar >>/var/log/bar.log 2>&1

--- crontab for user_two ---
*  *  * * * /bin/foo >>/var/log/foo.log 2>&1
16 10 * * * /bin/bar >>/var/log/bar.log 2>&1
```
6

for USER in `cut -d ":" -f1 </etc/passwd`; do crontab -u ${USER} -l 1>/dev/null 2>&1; if [ ! ${?} -ne 0 ]; then echo -en "--- crontab for ${USER} ---\n$(crontab -u ${USER} -l)\n"; fi; done

tharant · 2009-10-07 20:51:01 4
Show crontabs for all users

added echo "### Crontabs for $user ####"; to make clear whose crontab is listed.
This is sample output - yours may be different.
3

for user in $(cut -f1 -d: /etc/passwd); do echo "### Crontabs for $user ####"; crontab -u $user -l; done

harpo · 2012-07-11 12:25:56 6
list all crontabs for users

additionally use "find /etc/cron*" for cronscripts Show Sample Output
This is sample output - yours may be different.
```
cut -d: -f1 /etc/passwd | grep -vE "#" | xargs -i{} crontab -u {} -l
# m h  dom mon dow   command
# mysql backup
0 6 * * * /scripts/automysqlbackup.sh /dev/null 2>&1

no crontab for daemon
no crontab for bin
no crontab for sys
no crontab for sync
no crontab for games
```
1

cut -d: -f1 /etc/passwd | grep -vE "#" | xargs -i{} crontab -u {} -l

hoberion · 2009-06-18 16:49:52 9
Remove job from crontab by commandline

The "-u USER" is optional if root user is used
This is sample output - yours may be different.
1

crontab -l -u USER | grep -v 'YOUR JOB COMMAND or PATTERN' | crontab -u USER -

Koobiac · 2015-03-11 13:10:47 12
Add temporary <1m entries to old cron

Old cron doesn't allow periods
This is sample output - yours may be different.
1

for i in $( seq 0 5 55 ); do (crontab -l ; echo "* * * * * sleep $i; date >> ~/log.txt") | crontab -; done

swarzynski · 2022-04-04 09:56:40 586
Show crontabs for all users

added echo "### Crontabs for $user ####"; to make clear whose crontab is listed.
This is sample output - yours may be different.
0

for user in $(getent passwd|cut -f1 -d:); do echo "### Crontabs for $user ####"; crontab -u $user -l; done

harpo · 2012-07-11 13:06:17 4
Add a line to crontab using sed

I needed to add a line to my crontab from within a script and didn't want to have to write my own temporary file. You may find you need to reload the crond after this to make the change take effect. e.g.: if [ -x /sbin/service ] then /sbin/service crond reload else CRON_PID=`ps -furoot | awk '/[^a-z]cron(d)?$/{print $2}'` if [ -n "$CRON_PID" ] then kill -HUP $CRON_PID fi fi The reason I had CRON_HOUR and CRON_MINS instead of numbers is that I wanted to generate a random time between midnight & 6AM to run the job, which I did with: CRON_HOUR=`/usr/bin/perl -e 'printf "%02d\n", int(rand(6))'` CRON_MINS=`/usr/bin/perl -e 'printf "%02d\n", int(rand(60));'`
This is sample output - yours may be different.
-1

crontab -l | sed -e '$G;$s-$-'"$CRON_MINS $CRON_HOUR"' * * * /usr/bin/command >/dev/null 2>&1-' | crontab -

JohnGH · 2010-01-07 11:00:05 7
Update your system every day at the lunch time (12:00)
This is sample output - yours may be different.
-6

(crontab -e) 00 12 * * * apt-get update (/etc/init.d/cron restart)

osvaldofilho · 2009-10-29 12:45:26 4
Edit Crontab
This is sample output - yours may be different.
-7

crontab -e

theIndianMaiden · 2009-08-16 01:20:42 4
Edit Crontab

this lets you edit a crontab file (which may be used as a backup as well) and insert this into your crontab. this way is especially handy, when multiple users are working on one account (e.g. root)
This is sample output - yours may be different.
-7

vi ~/.crontab && crontab ~/.crontab

micha · 2009-08-16 08:09:15 9

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see who's using DOM storage a/k/a Web Storage, super cookies

Someone over at Mozilla dot Org probably said, "I know, let's create a super-duper universal replacement for browser cookies that are persistent and even more creepy and then NOT give our browser users the tools they need to monitor, read, block or selectively remove them!" . This will let you see all the DOM object users in all your firefox profiles. Feel free to toss a `| sort -u` on the end to remove dupes. . I highly recommend you treat these as "session cookies" by scripting something that deletes this sqlite database during each firefox start-up. . note: does not do anything for so-called "flash cookies"

Reboot without being root

For more, See: https://github.com/noureddin/bash-scripts/blob/master/user_scripts/userpower

Populate a folder with symbolic links to files listed in an m3u playlist.

This command will place symbolic links to files listed in an m3u playlist into a specified folder. Useful for uploading playlists to Google Music. prefix = The full path prefix to file entries in your .m3u file, if the file paths are relative. For example, if you have "Music/folder/song.mp3" in your list.m3u, you might want to specify "/home/username" as your prefix. list.m3u = Path to the playlist target_folder = Path to the target folder in which you would like to create symlinks

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)

Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

List only executables installed by a debian package

Maybe not clean with big package and too long argument. But return every file who can be executed.

Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

send DD a signal to print its progress

Sends the "USR1" signal every 1 second (-n 1) to a process called exactly "dd". The signal in some systems can be INFO or SIGINFO ... look at the signals list in: man kill

Recursively chmod all dirs to 755 and all files to 644

Remove Thumbs.db files from folders

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Commands using crontab (11)

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