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ugkbunb

Member

Registered: 2009-02-26

Posts: 227

[SOLVED] setopt noclobber >! doesn't overwrite file when used in cron

Basically I have noclobber set to true in .zshrc... this prevents accidently overwriting files with the pipe command...

When I run the command in a console without the >! command and noclobber set to true it properly detects the file exists and fails to overwrite it.

curl http://static.die.net/earth/mercator/1600.jpg > /home/geota/geota/.worldmap   
zsh: file exists: /home/geota/geota/.worldmap

Now when I exchange the pipe command to >! it properly overwrites the file when executed manually in the console... however if I have this command set in my crontab it instead of properly overwriting the file it just pipes it to a file named ! in my home directory...

# Reload Background Image
*/30 * * * * curl http://static.die.net/earth/mercator/1600.jpg >! /home/geota/geota/.worldmap && xfdesktop

I have tried a few different slight alterations to no avail such as

$(curl http://static.die.net/earth/mercator/1600.jpg >! /home/geota/geota/.worldmap)
`curl http://static.die.net/earth/mercator/1600.jpg >! /home/geota/geota/.worldmap`

Is there anyway I can get cron to excute the command and overwrite the file without setting noclobber to false?

Last edited by ugkbunb (2009-09-21 00:32:46)

neddie_seagoon

Member

Registered: 2009-08-23

Posts: 121

Re: [SOLVED] setopt noclobber >! doesn't overwrite file when used in cron

Have you explicitly set SHELL=/bin/zsh in your user's crontab? It may be running the commands with /bin/sh and thus not looking at your zsh settings.

ugkbunb

Member

Registered: 2009-02-26

Posts: 227

Re: [SOLVED] setopt noclobber >! doesn't overwrite file when used in cron

Have you explicitly set SHELL=/bin/zsh in your user's crontab? It may be running the commands with /bin/sh and thus not looking at your zsh settings.

hmm I just tried that and it had no effect. thanks though for the suggestion -- I guess it isn't so bad... I think since it is ignoring the noclobber command whether it is set or not... I can just drop the >! and leave it as >

marking this as solved

Last edited by ugkbunb (2009-09-21 00:33:03)

tuxce

Member

Registered: 2008-02-19

Posts: 56

Website

Re: [SOLVED] setopt noclobber >! doesn't overwrite file when used in cron

crontab provided by arch is dcron which is very basic:

Unlike other crond/crontabs, this crontab does not try to do everything
       under the sun.  Frankly, a shell script is much more able to manipulate
       the  environment  then  cron  and I see no particular reason to use the
       user's shell (from his password entry) to run cron commands  when  this
       requires  special  casing of non-user crontabs, such as those for UUCP.
       When a crontab command is run, this crontab runs it  with  /bin/sh  and
       sets up only three environment variables: USER, HOME, and SHELL.

ugkbunb

Member

Registered: 2009-02-26

Posts: 227

Re: [SOLVED] setopt noclobber >! doesn't overwrite file when used in cron

^^
Interesting... thanks for the information! It seems if I just slap the crap in a script and execute it from cron that it runs the script and hence the enviroment that the script was written for just fine.