You can get a complete list of shortcut cron settings by typing "man 5 crontab"

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This does work. Mac OS X uses Vixie Cron, the same that NetBSD uses. It also supports several other "special" settings.

cron 5 crontab

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man 5 crontab

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Thanks, I mistyped!

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Cronnix is a really nice interface to OS X's crontab and let's you modify the system crontab as well as any user crontab.

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if you rely on other processes running when you start your programm or your programm running before other programms start you should use the /Library/StartupItems-folder and adapt the StartupParameters.plist-file accordingly. just look for other startupitems and how they're done. p.e.:

mkdir /Library/StartupItems/MyProg
pico /Library/StartupItems/MyProg/MyProg and enter s/t like this:
-----------------------------------------------
#!/bin/sh
## My Prog is started and stopped here:
StartService ()
{
/COMMAND/TO/START/MyProg
}

StopService ()
{
/COMMAND/TO/STOP/MyProg
}
-------------------------------------------
chmod 755 /Library/StartupItems/MyProg/MyProg

if you wanna define some startup-order do:

pico /Library/StartupItems/MyProg/StartupParameters.plit and enter s/t like this (depends on your needs):
-------------------------------------------
{
Description = "My cool Prog";
Provides = ("MyProg");
Requires = ("DirectoryServices");
Uses = ("Disks", "NFS", "Network Time");
OrderPreference = "None";
}
------------------------------------------

shure the other thing works, too. but this is the standart-way to do this on osx and thats the way you get a message in the startup-box when your booting.

n.

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Just out of curiosity, what's the benefit of using this hint over putting things into your startup items under the Accounts pref pane?

John

---
Don't worry, it's out of control.

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Apps that you put in your startup field in account preference are launch at login not boot time.

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well, for most users, im not sure if there is a huge benefit. i know my school's sysadmins use crontabs to do some pretty useful things, but they would mostly not be relevant to single user machines. but, if say you wanted specific scripts to run for a user enrolled in a particular class whenever he logs in, or if he logs in on a particular day of the week...whatever, you can do things like that...prompt the user to change his password every 6 months, schedule backups, etc, etc.

powerful, if you care to learn how to use it.

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I found it to be more easy to startup command line programs. No need to create whole Startup item for that... just one line in the crontab.

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Except that Apple may or may not step on your modified crontab file in a system update. If you use a StartupItem (and put it in /Library/StartupItems where non-Apple ones belong), you don't have to worry about a system update silently causing your bootup tasks to stop working.

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Well, if you add a user crontab and not edit the system crontab (which u shouldnt to anyway) then it will never happen.

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Some commands have to be issued by a privileged user, so you couldn't put them in a user crontab. An example of this situation is to have (some) maintenance script run at start-up (like the periodic daily or periodic weekly scripts I pointed at in another comment). Since quite a few computers are off or asleep during the night, most computers have their periodic scripts run at irregular intervals.

I'd love to have further extensions to this, something like: @reboot,weekly (which would mean: at reboot, but at most once a week. This would add an administrative burden through). Alternatively: @reboot,monday (at reboot, but on mondays only).

Maarten

Maarten

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Normally (that is when you leave your computer on all the time) several maintenance scripts are run in the early morning hours. Since most people will leave their machines asleep during the night, or even turned off altogether, these maintenance scripts are never run. Depending on your reboot habits, you could add

@reboot periodic daily

to the master crontab in /etc/crontab. If you reboot infrequently, you could add @reboot periodic weekly and @reboot periodic monthly as well. weekly takes some time, but I believe the lot is run in the background anyway, so that isn't too bad (weekly updates refresh the locate database for quick command-line searches). Maarten

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What's the main differences between crontab -e

and modifying /etc/crontab?

i know crontab -e can modify a users crontab as well as a system one, but /etc/crontab seems separate from the command crontab -e

which one to use and modify?

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There is no difference afaik,
crontab -e just fires an editor to edit /etc/crontab (probably vi).

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There's a big difference!

crontab -e edits your user crontab (stored in something like /var/spool/cron/username, which should NEVER be edited directly!)

/etc/crontab is the "system" cron job. The format of this file is slightly different, since it takes an extra argument before the actual command to be run. That argument is the username under which the command will run, If you were administering a Mac that saw a LOT of users, this is a nice plan to manage crons for all them (and the users can't edit them!).

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Please is there a quick answer to this? - I want to run the python script: http://libgmail.sourceforge.net/ on startup to provide me with gmail pop access. Can I set a cron job that will load the python script in the background and keep it running? If so how? Right now I have it set up with an apple script to load the python script - but that is not very good because I have to leave the script running or else the python process will die. Thanks, iolaire

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I don't really mess with all this stuff that is the subject of the parent of this thread, but after reading your post, I thought this app might help you out: http://sveinbjorn.vefsyn.is/platypus.

From the Web site: "Platypus is a powerful developer tool for creating application wrappers around scripts, i.e. for creating MacOS X applications that execute a bundled script. Scripts can thus be run seamlessly from the graphical window environment, making elegant Mac OS X-native applications from scripts."

It may be overkill, or it may be just what you need. . . .

Jason

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My @reboot crontab job seems to not be running anymore now that I've upgraded to Leopard. I've verified that the cron job is still there by doing 'crontab -l', and it is.

I'm using this to run ssh-agent at reboot. Does Leopard ignore @reboot cron jobs?

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