Cron job shell script..

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# 1  
Old 08-07-2009
Cron job shell script..

Hey Guys,

i was trying out a shell script which has to remove a file for every 90 mins. this is the code i came up with .

$ crontab -e file1

file1 contains

30 1 * * * * rm -r /folder1/folder2/somefile.txt

Now i need the cron to run for every 90 mins. the problem with this is since the first field only accepts 0-59 i assumed it will add up the 30min and 1 hr as 90 mins, which i now think is incorrect. any suggestions ?

# 2  
Old 08-07-2009
yeah- that will run at 01:30 every day, not every 90 mins.

you could try running it every 30 mins, and set a flag file - test the age of the file, and if greater than, say 70 mins, run your command and retouch your flag file...

Or set a counter,

Or simply set a sleep timer in there, after which time it re-runs itself...

Or get your script to calculate next run time and reschedule using at

# 3  
Old 08-07-2009
if you can install fcron it will support more complex time arguments, if you are forced to use standard cron, try this.

0 0,3,6,9,12,15,18,21 * * * rm -r /folder1/folder2/somefile.txt

# 4  
Old 08-07-2009
*     *   *   *    *  command to be executed
-     -    -    -    -
|     |     |     |     |
|     |     |     |     +----- day of week (0 - 6) (Sunday=0)
|     |     |     +------- month (1 - 12)
|     |     +--------- day of month (1 - 31)
|     +----------- hour (0 - 23)
+------------- min (0 - 59)

Your entry will run at 1:30 am once a day. 90 minutes requires two separate crontab entries:

0 0,3,6,9,12,15,18,21 * * * [your cmd]

30 1,4,7,10,13,16,19,22 * * * [your cmd]

the [your cmd] is identical in the two entries. Also it is general MUCH better to specify
a shell script to run rather than a command. You simply edit the shell script as the complexity of the requirement morphs. read: users complain
# 5  
Old 08-07-2009

I guess this is GNU cron, but would this not work (if you have GNU cron!):
*/90 * * * * .....

man 5 crontab

# 6  
Old 08-07-2009
Originally Posted by scottn

I guess this is GNU cron, but would this not work (if you have GNU cron!):
*/90 * * * * .....

man 5 crontab

you mean vixiecron?
# 7  
Old 08-07-2009
Note: Not all crond implementations support the */90 slash syntax. The OP did not specify which one - FWIW.
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