learning cron

Anon

any good resources?

yelvington

Well, there's not a whole lot to it. Read

man crontab (the man page for the program)
man 5 crontab (describes the file format, the most useful part)
man cron (describes the daemon, but not particularly useful)

crontab -e edits your crontab (or a blank file if none exists) using the default editor, usually vi.

If you're on a Solaris system instead of Linux you may have a poor man page that lacks examples, so here is the example from the Linux manual.

EXAMPLE CRON FILE

use /bin/sh to run commands, no matter what /etc/passwd says

SHELL=/bin/sh

mail any output to `paul', no matter whose crontab this is

MAILTO=paul
#

run five minutes after midnight, every day

5 0 * $HOME/bin/daily.job >> $HOME/tmp/out 2>&1

run at 2:15pm on the first of every month -- output mailed to paul

15 14 1 $HOME/bin/monthly

run at 10 pm on weekdays, annoy Joe

0 22 1-5 mail -s "It's 10pm" joe%Joe,%%Where are your kids?%
23 0-23/2 echo "run 23 minutes after midn, 2am, 4am ..., everyday"
5 4 * sun echo "run at 5 after 4 every sunday"

polson

here's a fairly useful one :

http://www.faqts.com/knowledge_base/view.phtml/aid/1005/fid/436

this too :

http://schvin.net/writings/crontab.html

Anon

You'll be dumped into the default editor unless you set one explicitly. For most systems this is vi. vi is about the worst editor to use for a newbie (for one, you won't know how to exit out of it).

I would advise either having a page with basic vi commands available or setting your $EDITOR environment variable to something less hostile (like pico or ee).

type:
echo $EDITOR
to see what your editor is set to.

on csh or tcsh you need :
setenv EDITOR "pico"
and on bash
export EDITOR=pico

You should be able to type either from the command prompt. To keep it permanent you can put it in your .cshrc or .profile/.bash_profile file.