crontab - User crontab manipulation
crontab -c [user] file
crontab -l [user]
crontab -r [user]
The crontab program allows users to manipulate their personal crontab
files. These files are hidden in /usr/spool/crontabs/user where user is
the login name of a given user. The system daemon cron uses these
crontabs, among others, to run tasks that are to be repeated at regular
intervals. See crontab(5) on what a good crontab file should look like.
Only the superuser can specify a user name to manipulate the crontab of a
given user. Any other user can only touch their own crontab file.
-c [user] file
Install file as the crontab file of user.
List the crontab file of user to standard output.
Remove the crontab file of user.
-p Tell cron to reload its tables. Useful for system administrators to
signal a change to any of the system crontab files. Changes made by
the crontab program are signalled automatically. (Mnemonic: -p =
/usr/spool/crontabs/user Per user personal crontab file.
Crontab preparses a new crontab and only installs it if correct. All
errors are sent to standard error, messages about installing a new table
and telling cron to reload are sent to standard output.
Crontab misses a -e option that other implementations of this command
allow one to edit the current crontab and install the result. Seems
quite handy until you try to install a new crontab from an automated
script. That's why this command has a -c option that installs a prepared
crontab file. Use
crontab -l >/tmp/tab
crontab -c /tmp/tab
to get the same effect as crontab -e.
Kees J. Bot (email@example.com)