How to disable everything in crontab -l?

First, back up the crontab:

crontab -l > my_cron_backup.txt

Then you can empty it:

crontab -r

To restore:

crontab my_cron_backup.txt
crontab -l

crontab -e then comment out each line you don't want to run with #.

Do you have root access? Just pause cron

sudo /etc/init.d/crond stop

Then restart it when you're ready

sudo /etc/init.d/crond start

If you are using vi as editor, then just enter :%s/^/#/ in command mode. In all lines (%), it substitutes (s///) the begin of line (^) with a hash (#).

Wasn't happy with the options above since they weren't one liners.

To disable crontab -l | perl -nle 's/^([^#])/# $1/;print' | crontab

To enable crontab -l | perl -nle 's/^#\s*([0-9*])/$1/;print' | crontab

usage example ( edited to show it doesn't disable comments)

$ crontab -l
# Comment
0 0 * * 0 /opt/something.sh

$ crontab -l|perl -nle 's/^([^#])/# $1/;print'|crontab
$ crontab -l
# Comment
# 0 0 * * 0 /opt/something.sh

$ crontab -l|perl -nle 's/^#\s*([0-9*])/$1/;print'|crontab
$ crontab -l
# Comment
0 0 * * 0 /opt/something.sh

Tested this on RHEL and AIX , and should work out of the box without anything needed to be installed

In my limited testing, setting the shell to /bin/false works. You will still see /opt/job.sh executing in your logs, but it will be a noop:

SHELL=/bin/false

*/1 * * * *    root  /some/job.sh

In any flavor of Unix/Linux that I know of:

mv /var/spool/cron  /var/spool/cron_is_disabled

This:

• disables crontabs of all users
• but not system /etc/crontab (/etc/cron.daily. etc.)
• persists across a reboot
• is a one-liner, duh :)

I got the idea from the answer provided by @segaps

To disable:

crontab -l | awk '{print "# "$1}' | crontab

To enable:

crontab -l | cut -c 3- | crontab

The only problem with the solution provided by segaps, is that it will uncomment the jobs, that are already commented by the user.

To do this, using nano as the editor:

sudo env EDITOR=nano crontab -e

then comment out each line you don't want to run with #

You can use the following like so:

crondisable
cronenable

crondisable some_other_user
...

The zsh code (put in your .zshrc):

ecerr () {
print -r -- "$@" >&2
}
crondisable() {
        local user="${1:-$(whoami)}"
        local cronpath="/tmp/$user.cron.tmp"
        test -e "$cronpath" && {
        ecerr "There is already a disabled crontab at $cronpath. Remove that manually if you want to proceed."
        return 1
        }
        crontab -l -u $user > "$cronpath"
        crontab -r -u $user
}
cronenable() {
        local user="${1:-$(whoami)}"
        local cronpath="/tmp/$user.cron.tmp"
        test -e "$cronpath" || {
        ecerr "No disabled cron at $cronpath"
        return 1
        }
        crontab -u $user "$cronpath"
        mv "$cronpath" "${cronpath}.bak"
}