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Old 10-25-2004, 08:23 AM   #1
nitaish
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Registered: Oct 2003
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Setting a cron


Hello,
I want to setup a cron to run a certain command each hour in my server. I am running a Red Hat 7.2 RPM version. Can somebody tell me how to add the cron.

Thanks
Regards
Nitesh N
 
Old 10-25-2004, 08:33 AM   #2
cadj
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Registered: Aug 2003
Location: Melbourne Australia
Distribution: LinuxMint Elyssa
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i have a script that updates my ad blocking host file once a day, i set cron to run this script at 17:30

to set this cron, i use the command

crontab -e

the file is simple to edit, use the following format

min hour day week month command

so if you want to run /bin/myscript at 17:30

30 17 * * * /bin/myscript

im using debian so im not sure how this works on other distros.


another way is to create an executable script in /etc/cron.hourly , the script may look like

#---------
#!/bin/bash
wget http://someonewhocares.org/hosts/hosts
cat hosts >/etc/hosts
#----

after the script is made, make sure you make it executable with

chmod +x myscript

hope ive been of some help
 
Old 11-01-2004, 08:50 AM   #3
nitaish
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Registered: Oct 2003
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setting up a cron

Hi,
Thanks for the help. I think I am able to understand how to setup a cron a bit. But here I am a little confused. What does the following mean ?

#!/bin/bash

In some cron jobs, I have found that instead of #!/bin/bash, there is #!/bin/sh

What is the difference between the two and what should be used while setting up a daily cron ?

Kindly advise.

Thanks
Regards
Nitaish
 
Old 11-01-2004, 07:42 PM   #4
trickykid
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Registered: Jan 2001
Posts: 24,133

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Re: setting up a cron

Quote:
Originally posted by nitaish
Hi,
Thanks for the help. I think I am able to understand how to setup a cron a bit. But here I am a little confused. What does the following mean ?

#!/bin/bash

In some cron jobs, I have found that instead of #!/bin/bash, there is #!/bin/sh

What is the difference between the two and what should be used while setting up a daily cron ?

Kindly advise.

Thanks
Regards
Nitaish
That's the shell it uses to execute the commands. Most or some Linux distros just have sh point to bash. bash is a enhanced version of sh.
 
Old 11-01-2004, 08:16 PM   #5
cadj
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Location: Melbourne Australia
Distribution: LinuxMint Elyssa
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its so the system knows how to execute the script, eg at the top of my perl scripts i put

#!/usr/bin/perl

which tels the system to run the script with perl
 
Old 11-03-2004, 01:15 AM   #6
nitaish
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Registered: Oct 2003
Posts: 17

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Hi Folks,
Thanks for the help. I have installed qmHandle in the server and have setup a cron which runs daily. It looks something like this

#############

#!/bin/bash

<command>

#############

I want to know if the cron is running properly. Can I write a script which will write the output of the result in a text file when the cron runs successfully? If yes, then how do I write it ? Kindly suggest.

Thanks
Regards
Nitaish
 
Old 11-03-2004, 07:43 AM   #7
cadj
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Registered: Aug 2003
Location: Melbourne Australia
Distribution: LinuxMint Elyssa
Posts: 373

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to test mine, i had it running on an hourly basis

write a script "test" and put it in your / dir

#!/bin/bash
echo the cron has worked >/cron.test

and make sure its executable by

chmod +x test

then in your crontab

1 * * * * /test

every one min it should make a file cron.test in your / dir
 
  


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