Feb 28, 2014  I am a Unix newbie trying to make a crontab for my Mac OS X that automatically turns on/off my wifi at specified times. The following commands both work when I enter them in the Terminal: networksetup -setairportpower en1 off. Networksetup -setairportpower en1 on. However, I can't get even this simplest of cron files to work. May 03, 2017  I would like to send an email to user@example.com instead of default system root user for crond service on a Linux or Unix-like system. How do I change the email settings under crontab file on a Linux or Unix-like systems? A crontab file contains instructions to the cron daemon. It wakes up every minute, examining all stored crontabs, checking each command to see if it should be run in the. Jan 25, 2007  Creating your first crontab job is a three-part process: Prepare the absolute path to the program or script that you want to run Create a text file containing a line to schedule the job as described above for crontab fields Upload the text file to your system cron When preparing program to run or creating Continue reading Creating a crontab.

With the Unix underpinning of Mac OS X, it is possible to run crontabs which are scripts or programs that run on a set schedule. The problem for many users is that crontabs need to be set from the command line in Unix, but Koch und Schmidt Systemtechnik GbR has released a new product called CronniX that changes that. CronniX allows Mac OS X users to edit and install crontabs from a GUI-based app. According to Koch & Schmidt:

I tried running crontab on my Mac for the first time and got the following: $ crontab -e crontab: no crontab for User - using an empty one crontab: subl -w: No such file or directory crontab: 'subl -w' exited with status 1 I've never used crontab on my Mac and have no idea why it's trying to reach the sublime command line tool.

CronniX is a little tool to edit and install a 'crontab'. For those who donit know what crontab is, see the description below or 'man crontab' in the Terminal for more details. In short, itis a scheduler that allows you to run shell commands or scripts at certain times or intervals. Itis a very powerful tool.

New in 1.1

• 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.
• Apr 27, 2020  Some advanced Mac users may have noticed that certain shell scripts with cron, cron jobs, and crontab are either not working at all, or not able to function properly in the newest versions of MacOS, notably Mojave 10.14, Catalina 10.15 and later.

• Drag and drop support. As suggested by a user, CronniX now features drag and drop. Upon dropping a text selection on a line, it is inserted as a command in the command field. If you drop a file its name is inserted along with a prepended 'open'. This can be used to insert AppleScripts. If the drop is not on a line but rather the table view, a new line is inserted.
• Open for different user. The file menu item 'Open For User' will open a dialog that allows you to open another useris crontab. Note that you have to be super user ('root') to be able to do this. Crontab (the underlying Unix tool) will deny access to other useris crontabs for any user but the super user.
• Online help.
• Rewritten in Objective C. This makes CronniX start up faster and use less memory than the Java version.

How do I use it?
The interface of CronniX is rather .. simple. It features a 'New line', 'Remove line', and 'Write' button, which incidentally perform the actions on the labels. Your current crontab is read automatically after startup. You can edit the fields and install it by pressing 'Write'. Note that the programis data structure is only updated if you press enter or tab after editing a field. This is the normal spreadsheet behavior of the underlying NSTableView object. Pressing 'New line' adds a new line with the default settings as shown in the screenshot to your crontab. This line should also give a picture of the crontab syntax for those who donit know (or remember) the structure.

You can find more information on the product at Koch und Schmidt Systemtechnik GbRis Web site.

Crontab Run As User

Click here to return to the 'Using the 'cron' scheduler' hint

I should note that there is a gui frontend for editing your crontab available. It's called CronniX, see www.koch-schmidt.de/cronnix. Incidentally, the author is called Sven, too.. ;-)

Thanks Sven - it's posted somewhere here as a tip, too. Good program that makes configuring cron much more straightforward!
-rob.

That URL is now spam.

If you cp /etc/crontab and use that as your base crontab, make sure you don't keep the user specification. Haxm for mac sierra solved. I changed 'root' to my user and spent hours trying to figure out why my crontab wouldn't work. It was trying to run my username as a command!
On user specific crontabs, do not specify a user to run the command as. The crontab located at /etc/crontab is the system-wide crontab. Root is specified in each so those commands are run as root. The user, root, doesn't have a crontab at all!!
This gave me a headache for a while, but I'm glad I understand it now.

Thankyou so much for that. Just my first time at setting up a cron for an rsync and taken me two hours of searching to find out why nothing was happening.. You are a genious!
Cheers

Some other problems you may have:
When I opened up a GUI application using crond:
sh /usr/bin/open ~/Application.app
It did not seem to work.
I changed it to:
/usr/bin/open ~/Application.app >& /dev/null
And it worked.
I suspect not having the redirect-all at the end causes security problems as I not sure what uid's console is attached to the cron process at that time, and may be the cause of an error I received:
'com.apple.launchd[1] (0x10c650.cron[14768]): Could not setup Mach task special port 9: (os/kern) no access'
Hope this helps some people out.
PS: I used it to create template mails from an automator script I ran each morning to find people I know what has a birthday that same day.

Oh wow, I hope that works! I've been so frustrated with cron and iCal script alarms not working in the middle of the night!
Rob

Rather than copy the system cron file and edit in a text editor you can use the command
crontab -e
which brings up your crontab for editing in the 'vi' editor. When you save your changes it will then parse the crontab you have set up and warn you if there are any obvious errors in it.

/project-software-for-mac-os-x.html. man crontab
man 5 crontab
man vi

TextWrangler's (and its 'poppa' BBEdit's) edit command line tool can be used to edit the crontab file, following the setup instructions on its man page -- note that you have to write a little 'helper' shell script to invoke

No Crontab For Root

edit with the -w option in order to work around a limitation in crontab.

I've used this for years, but it broke suddenly with the TextWrangler 3.5.3 update, with the error 'crontab: temp file must be edited in place'. This is because the new version of TextWrangler brought in some code from BBEdit which observes a new expert preference. To fix it, quit TextWrangler and execute the following in Terminal: I can't speak to the implications of disabling safe saves, however.

crontab file locations under Mac OSX 10.6 are now:
/usr/lib/cron/tabs

Found this old thread and while most of it seems to be helpful to me, there are some things I can't seem to make happen.
I'm completely new to *nix operating systems and just now getting into the guts of the OSX OS, so vim and the Terminal are fairly new to me.
That said, I have a need to run a cron process in root and I can't seem to make it happen.
I can't seem to get into the /usr/lib/cron/tabs directory, and I can't figure out what I need to do to read the cron.deny file in the /usr/lib/cron directory.
Thanks for any help.
Any vi tutorials or anything as well as any bash tutorials would be helpful as well.