Hi All,
Please help me in understanding the crontab entries and also below queries

1. how can we set a crontab entry
2. from where the cronjob will run( if default)
3. you can we specify the location from which the cronjob should run.
4. how can we capture the output of the cronjob.

Thanks
Satish

To begin with, read the man pages of cron and crontab (both crontab(1) and crontab(5)). This probably will answer most of your questions.

please help me for this 2 questions

1 from where the cronjob will run( if default)
2. Can we specify the location from which the cronjob should run.


Thanks
satish

crontab if not specified will run fron root users account ,location as in which program u want to run or what please be more clear,the man pages will be good place to start with and also you can capture the output of crontab by redirecting the output to some file instead of /dev/null.

Hi

If you want a specific user to run a crontab (root, myself, yourself, etc) then the easy way is to log into that users account and create the crontab entry:
"crontab -e"
This gives you YOUR OWN (or that users) crontab file to edit, using say "vi", or "gvim, whatever is the default editor.

Save and exit the changes with:
":wq" from inside the text editor.

Use "crontab -l" to view the YOUR OWN (or that users) crontab contents - without the risk of editing it.

Bye
GrahamB

Hi Satish:

Your last question: how can we capture the output of the cronjob.

Use the directional parameters "> $file" and/or ">> $file" for example. Anything that goes to stdout would then be routed to $file. Any other stdoutput would, for example go into the mail of the user who has called the crontab-job.

Try something like this:
My practice is to get output from the specific functions in the program to output to log files. For example the program "./backup_mysql.sh" may generate files that are of interest to specific users.

Above the redirection is to a log-file describing the overall performance of the program and the variable used by "./backup_mysql.sh". This logs data that would be of interest to the administrator, for example.

Note: "2>&1" is also a redirection. Another story!

regards
GrahamB

Hi grahamb,

Thanks for your info. 1 more quick questions as you said the below

"2>&1" is also a redirection. Another story!


can you please explain this concept also. it will very helpful .


Thanks
Satish

Hi

the 2 >&1 represent standard error that is represented as 2 should also be redirected where the standard ouput has been directed it is a posix notation and can be found in man sh posix
hope this will clear your doubt.
Goodluck

Got the info and cleared my doubt
Thanks for all of you ,


Thanks
satish