HowTo: Add Jobs To cron Under Linux or UNIX?

by on April 16, 2006 · 208 comments· LAST UPDATED January 21, 2014

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How do I add cron job under Linux or UNIX like operating system?

Cron job are used to schedule commands to be executed periodically. You can setup commands or scripts, which will repeatedly run at a set time. Cron is one of the most useful tool in Linux or UNIX like operating systems. The cron service (daemon) runs in the background and constantly checks the /etc/crontab file, and /etc/cron.*/ directories. It also checks the /var/spool/cron/ directory.

crontab command

Tutorial details
DifficultyIntermediate (rss)
Root privilegesYes
Requirementscrond
Estimated completion time20m
crontab is the command used to install, deinstall or list the tables (cron configuration file) used to drive the cron(8) daemon in Vixie Cron. Each user can have their own crontab file, and though these are files in /var/spool/cron/crontabs, they are not intended to be edited directly. You need to use crontab command for editing or setting up your own cron jobs.

Types of cron configuration files

There are different types of configuration files:

  1. The UNIX / Linux system crontab : Usually, used by system services and critical jobs that requires root like privileges. The sixth field (see below for field description) is the name of a user for the command to run as. This gives the system crontab the ability to run commands as any user.
  2. The user crontabs: User can install their own cron jobs using the crontab command. The sixth field is the command to run, and all commands run as the user who created the crontab

Note: This faq features cron implementations written by Paul Vixie and included in many Linux distributions and Unix like systems such as in the popular 4th BSD edition. The syntax is compatible with various implementations of crond.

How Do I install or create or edit my own cron jobs?

To edit your crontab file, type the following command at the UNIX / Linux shell prompt:
$ crontab -e

Syntax of crontab (field description)

The syntax is:

 
1 2 3 4 5 /path/to/command arg1 arg2
 

OR

 
1 2 3 4 5 /root/backup.sh
 

Where,

  • 1: Minute (0-59)
  • 2: Hours (0-23)
  • 3: Day (0-31)
  • 4: Month (0-12 [12 == December])
  • 5: Day of the week(0-7 [7 or 0 == sunday])
  • /path/to/command - Script or command name to schedule

Easy to remember format:

* * * * * command to be executed
- - - - -
| | | | |
| | | | ----- Day of week (0 - 7) (Sunday=0 or 7)
| | | ------- Month (1 - 12)
| | --------- Day of month (1 - 31)
| ----------- Hour (0 - 23)
------------- Minute (0 - 59)

Your cron job looks as follows for system jobs:

1 2 3 4 5 USERNAME /path/to/command arg1 arg2

OR

1 2 3 4 5 USERNAME /path/to/script.sh

Example: Run backup cron job script

If you wished to have a script named /root/backup.sh run every day at 3am, your crontab entry would look like as follows. First, install your cronjob by running the following command:
# crontab -e
Append the following entry:
0 3 * * * /root/backup.sh
Save and close the file.

More examples

To run /path/to/command five minutes after midnight, every day, enter:
5 0 * * * /path/to/command
Run /path/to/script.sh at 2:15pm on the first of every month, enter:
15 14 1 * * /path/to/script.sh
Run /scripts/phpscript.php at 10 pm on weekdays, enter:
0 22 * * 1-5 /scripts/phpscript.php
Run /root/scripts/perl/perlscript.pl at 23 minutes after midnight, 2am, 4am ..., everyday, enter:
23 0-23/2 * * * /root/scripts/perl/perlscript.pl
Run /path/to/unixcommand at 5 after 4 every Sunday, enter:
5 4 * * sun /path/to/unixcommand

How do I use operators?

An operator allows you to specifying multiple values in a field. There are three operators:

  1. The asterisk (*) : This operator specifies all possible values for a field. For example, an asterisk in the hour time field would be equivalent to every hour or an asterisk in the month field would be equivalent to every month.
  2. The comma (,) : This operator specifies a list of values, for example: "1,5,10,15,20, 25".
  3. The dash (-) : This operator specifies a range of values, for example: "5-15" days , which is equivalent to typing "5,6,7,8,9,....,13,14,15" using the comma operator.
  4. The separator (/) : This operator specifies a step value, for example: "0-23/" can be used in the hours field to specify command execution every other hour. Steps are also permitted after an asterisk, so if you want to say every two hours, just use */2.

How do I disable email output?

By default the output of a command or a script (if any produced), will be email to your local email account. To stop receiving email output from crontab you need to append >/dev/null 2>&1. For example:
0 3 * * * /root/backup.sh >/dev/null 2>&1
To mail output to particular email account let us say vivek@nixcraft.in you need to define MAILTO variable as follows:
MAILTO="vivek@nixcraft.in"
0 3 * * * /root/backup.sh >/dev/null 2>&1

See "Disable The Mail Alert By Crontab Command" for more information.

Task: List all your cron jobs

Type the following command:
# crontab -l
# crontab -u username -l

To remove or erase all crontab jobs use the following command:
# Delete the current cron jobs #
crontab -r

## Delete job for specific user. Must be run as root user ##
crontab -r -u username

Use special string to save time

Instead of the first five fields, you can use any one of eight special strings. It will not just save your time but it will improve readability.

Special stringMeaning
@rebootRun once, at startup.
@yearlyRun once a year, "0 0 1 1 *".
@annually(same as @yearly)
@monthlyRun once a month, "0 0 1 * *".
@weeklyRun once a week, "0 0 * * 0".
@dailyRun once a day, "0 0 * * *".
@midnight(same as @daily)
@hourly Run once an hour, "0 * * * *".

Examples

Run ntpdate command every hour:
@hourly /path/to/ntpdate
Make a backup everyday:
@daily /path/to/backup/script.sh

More about /etc/crontab file and /etc/cron.d/* directories

/etc/crontab is system crontabs file. Usually only used by root user or daemons to configure system wide jobs. All individual user must must use crontab command to install and edit their jobs as described above. /var/spool/cron/ or /var/cron/tabs/ is directory for personal user crontab files. It must be backup with users home directory.

Understanding Default /etc/crontab

Typical /etc/crontab file entries:

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/
# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly

First, the environment must be defined. If the shell line is omitted, cron will use the default, which is sh. If the PATH variable is omitted, no default will be used and file locations will need to be absolute. If HOME is omitted, cron will use the invoking users home directory.

Additionally, cron reads the files in /etc/cron.d/ directory. Usually system daemon such as sa-update or sysstat places their cronjob here. As a root user or superuser you can use following directories to configure cron jobs. You can directly drop your scripts here. The run-parts command run scripts or programs in a directory via /etc/crontab file:

DirectoryDescription
/etc/cron.d/ Put all scripts here and call them from /etc/crontab file.
/etc/cron.daily/ Run all scripts once a day
/etc/cron.hourly/ Run all scripts once an hour
/etc/cron.monthly/Run all scripts once a month
/etc/cron.weekly/Run all scripts once a week

How do I use above directories to put my own scripts or jobs?

Here is a sample shell script called clean.cache. This script is created to clean up cached files every 10 days. This script is directly created at /etc/cron.daliy/ directory. In other words create a text file called /etc/cron.daily/clean.cache as follows.

 #!/bin/bash
# A sample shell script to clean cached file from lighttpd web server
CROOT="/tmp/cachelighttpd/"
 
# Clean files every $DAYS
DAYS=10
 
# Web server username and group name
LUSER="lighttpd"
LGROUP="lighttpd"
 
# Okay, let us start cleaning as per $DAYS
/usr/bin/find ${CROOT} -type f -mtime +${DAYS} | xargs -r /bin/rm
 
# Failsafe 
# if directory deleted by some other script just get it back 
if [ ! -d $CROOT ]
then
        /bin/mkdir -p $CROOT
        /bin/chown ${LUSER}:${LGROUP} ${CROOT}
fi

Save and close the file. Set the permissions:
# chmod +x /etc/cron.daily/clean.cache

How do I backup installed cron jobs entries?

Simply type the following command to backup your cronjobs to a nas server mounted at /nas01/backup/cron/users.root.bakup directory:
# crontab -l > /nas01/backup/cron/users.root.bakup
# crontab -u userName -l > /nas01/backup/cron/users.userName.bakup

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{ 208 comments… read them below or add one }

1 umesh August 30, 2006 at 6:10 am

hi
i want to mail for few members for every 15 mintes .i have worte php script stored as mail.php i want to set cronjob . i don’t no how to set corn commad or path i am useing cpanel
can u help me

Reply

2 nixCraft August 30, 2006 at 6:41 pm

Type crontab -e command:
crontab -e

Append following job:
15 * * * * /path/to/script.php

Save and close the file.

Reply

3 Techie Talks July 9, 2010 at 3:02 am

Above is easiest way of creating one.

Reply

4 reggy February 11, 2011 at 3:56 pm

hi nixcraft
you mean “Save and close the file.”

and how to execution this file??

sorry i’am newbie :D

Reply

5 arora February 22, 2011 at 10:39 am

saving the above file will help as it will excecute on first 15th min of every hour.

Reply

6 Jimmy August 25, 2011 at 10:28 am

Old thread, but found this by misstake :)

Think you need to put:
0,15,30,45 * * * * /path/to/script.php

if you want it to execute every 15 minutes.

Reply

7 anshumantrivedi October 5, 2011 at 6:44 am

0,15,30,45,60 * * * * /path/to/script.php

you can try this……….

Reply

8 chiks November 8, 2011 at 3:49 pm

urs is right…………but if u r a unix professional then u should follow mine

and (this is d best way to schedule in every 15 min)

*/15 * * * * /path/to/script.php

Reply

9 dilip varma December 18, 2013 at 3:44 pm

for the best practise use

*/15 * * * /path/to/php_script

Reply

10 srini August 25, 2014 at 8:31 am

I believe i should be like,
15,30,45,00 * * * * /path/to/script.php

Reply

11 David W. Jensen December 27, 2006 at 2:45 am

Using Puppy Linux at the moment. How does one check to see if the cron daemon is running.?
I have a file that works from the command line.
“/home/dwj/CRONY/cronf.01″ which simply makes a statement on the monitor screen. I want cron to be able to put a variety of messages on the monitor screen at various times through the day & week. [ A separate file for each message of course.]
But so far nothing I had tried works. In /var/spool/cron/crontabs/dwj [ my crontab file which was created using Puppy’s GUI ‘gcrontab’ within their control panel, bottom selection.].
The items in the fields look correct to me vis:
“01-59/6 * * * * /home/dwj/CRON/cronf.01″

Which is supposed to mean from minute 01-59 each
6 second interval = do the file in field #-6.
What else am I missing or do not understand.?

TIA for any & all help rendered.

Dwj 73 w 0 r m v LONG LIVE LINUX

Reply

12 chiks November 8, 2011 at 4:01 pm

david u know cron job wakes up each and every minute….so u can’t
write a cron script which is supposed to run each and every second.
for that u have to write a script and another one u can schedule a particular job
like 7:30:45.
for dis u have to write a script at 7:30 first.give this script name to a.sh.then….
in unix there s a concept called wrapper script in which u will include the “sleep”
command
write another script called b.sh
in there write
sleep 44 a.sh
then execute it. it will run at 7:30:45

Reply

13 nixCraft December 27, 2006 at 8:46 am

David,

Crontab is designed to work with minutes and upwards it cannot wake up and run task every second or every 6 second later. cron is not really
designed for such frequent runs.

You need to start your script in background
/home/dwj/CRON/cronf.01 &

in script put logic as follows
while [ true ]; do
sleep 6
# add rest of commands
Done

Reply

14 JDS January 5, 2007 at 4:00 pm

The response to “how to run every 15 minutes” is wrong. The answer given:

15 * * * * /path/to/script.sh

will run the thing every hour, at the 15 minute mark. (9:15, 10:15, etc)

The proper answer is:

0,15,30 * * * * script.sh

or

0-59/15 * * * * script.sh

(depends on your version of cron)

Reply

15 Manoj October 5, 2010 at 5:10 am

we can run cron job every 15 min using following expression.
*/15 * * * * script.sh

Reply

16 Chitra July 24, 2013 at 9:52 am

Thanks for this post.

Reply

17 Ian Mc March 10, 2011 at 11:42 am

Surely 0,15,30,45 * * * * script.sh

???

Reply

18 zane matthew January 26, 2007 at 4:00 pm

thanks for the help, im at working installing mrtg and setting up my crontab files for the first time

Reply

19 ashish February 20, 2007 at 7:09 pm

why doesn’t crontab work for me .
the crond is running bbut what i want is not happening
/var/spool/cron is unreadable
also crontab -l correctly lists what I want
35 * * * * /usr/bin/gedit

Reply

20 rahul January 30, 2013 at 8:22 am

here u want to write */35 * * * * /usr/bin/gedit

Reply

21 ashish February 20, 2007 at 7:13 pm

even at does nothing for me
atd is running

Reply

22 ashish February 20, 2007 at 7:14 pm

even at does nothing for me
atd is running
and when I press atq it lists the time and everything
but when the time comes the atq displays nothing

Reply

23 vengadesh March 14, 2007 at 9:06 am

I have a question , How to run Cron for 5 seconds.please advice me .Reply fast

Reply

24 rocky March 16, 2007 at 8:36 am

vengadesh,

You can’t uss crond for seconds

Reply

25 Tarachand March 20, 2007 at 5:04 am

hi

I want to fire cron job at the interval of every 10 minutes, how to write entry in crontab.

regards

Tarachand

Reply

26 George March 22, 2007 at 1:35 pm

Is it possible to have cron run something on the second Saturday of the month? Also, is it possible to have cron run somthing 2 days prior to the end of each month?

Reply

27 Jeremy Hannah March 23, 2007 at 8:29 pm

Does the cron job have to reside in /var/spool/cron/crontabs, or can the cronjob reside anywhere?

Reply

28 nixCraft March 24, 2007 at 4:55 am

Jeremy,

Yup it is the default location under /var file system. You can change this location by recompiling software.

Reply

29 Aravind Miryala April 7, 2007 at 3:32 pm

I want to schedule cron jobs for First Saturday of Every MOnth. Your help is appreciated

Reply

30 nixCraft April 7, 2007 at 9:53 pm

Aravind,

You need to write a smart script that will detect First Saturday of Every Month as you can not write such cron job. You can also try following trick:
00 01 1-7 1-12 * if [ "$(date +%a) = "Sat" ]; then /path/to/script.sh; fi

Add additional logic in /path/to/script.sh to detect First Sat of each month.

Reply

31 Pankaj Sain May 5, 2011 at 11:31 am

We can do this by the following also..

01 00 1-7 * 6 /path/to/script.sh

However no need to reply on this so old, but only for the new comers..

This Site provides really great info. for newbies and the masters too.

Reply

32 lucky February 28, 2012 at 4:22 pm

Hi,
pankaj can u tell me how to schedule second saturday of every month and explain how job run on every first saturday above cronjob.

Reply

33 Valli April 19, 2007 at 2:42 pm

What does 00 14 29 12 4
mean?

Reply

34 John T. April 19, 2007 at 7:28 pm

Vali,

# Use the hash sign to prefix a comment
# +—————- minute (0 – 59)
# | +————- hour (0 – 23)
# | | +———- day of month (1 – 31)
# | | | +——- month (1 – 12)
# | | | | +—- day of week (0 – 7) (Sunday=0 or 7)
# | | | | | +- command to be executed
# | | | | | |
# * * * * * command
0 14 29 12 4 /path/to/command

command will be run at 2pm Dec 29th in addition to every Thursday in December I believe.

Reply

35 Sahithi February 23, 2014 at 8:33 am

In addition to every thursday? or will it run only if Dec29th is thursday

Reply

36 Lakshmi Shastry April 26, 2007 at 7:44 am

I need to write a cron expression which fires every 5 hours from the given start time. Ex:- If 8.30 am is my start time then the cron expression will be something like “30 8,0-23/5 * * *”. But this fires in the time sequence like at 8.30, 10.30, 15.30, 20.30, 00.30, 10.30 etc…
But what i need the time sequence is 8.30, 13.30, 18.30, 1.30, 6.30, 11.30, 16.30, 21.30, 2.30… which means that fire should occur for the specified start time and every 5 hours after that. Can anyone help me with the cron expression to represent the same. Thanks a lot in advance.

Reply

37 rahul November 15, 2010 at 1:09 pm

hey lakshmi ..
firstly you check this command “crontab -l Display your crontab file.” that show you presentally crontab.After that see your chron scrip ki chang or not .there is some two hours interval . You want run this scrip in all day of week. Then in this case you use this script.. “30 8:30,13:30,18:30,1:30,6:30,11:30,16:30,21:30,2:30 * * # give your destinestion path#

and other wire u check the chmod permision if this script solve your problem .so plz reply

Reply

38 rahul November 15, 2010 at 1:11 pm

Then in this case you use this script.. “30 8,13,18,1,6,11,16,21,2 * * # give your destinestion path#
sorry for that check this script

Reply

39 vinod April 27, 2007 at 3:24 pm

i hope
30 1-23/5 * * * /aaa.sh
will work

Reply

40 GC Hutson May 26, 2007 at 9:18 pm

Since CRON cannot be used to schedule tasks by the second, what can be used/written/done to perform tasks as such?

Reply

41 Ap_1 May 30, 2007 at 5:35 am

Hi,
I added 1 enrty in crintab using crontab -e,i added below line in that file
0 23 * * 1-5 root echo “I will run at 11″

but after 11:00 clock also its not running….
y any idea ???

I checked,Cron shell is running……then y that command didnt run..
Plz help regarding this

Reply

42 Johan August 15, 2007 at 6:06 pm

Hello,

When i try to run crontab i get the following error message “failed user root parsing”.

And the cron is not executing anything.

The command crontab -l indicates that everything is fine and that i have scheduled a command correctly.

Also checked that the service is running “crond”

cant get cron to work please help!

I am using Puppy linux 2.16

Thanks for help, my email is: Johan@mediavisiongroup.se

Reply

43 Ivan Versluis December 19, 2007 at 10:22 am

Thank you. I needed some help on scheduling my ntpdate in a virtual linux machine.

Reply

44 vasanthan January 17, 2008 at 2:53 pm

problem with setting cronjob..

i woud like to kow how to run a mail.php
file everday..on my server..5 0 * * * /path/to/command..the thing is i dont know the
command ..please help me..

Reply

45 lalith January 18, 2008 at 10:55 am

Can any one help me iam using Debain 3.0 server when iam setup a file for cron job,it was not working.

Reply

46 sateesh January 18, 2008 at 11:40 am

we can use */15 * * * * cmd also to run every 15 minutes

regards.
sateeshlinux.blogspot.com

Reply

47 neo January 21, 2008 at 10:36 am

Hi,
My cron manage to execute at the desired time but the email i received is “permission denied”. I copy and paste the message below

“/bin/sh: /usr/bin/lynx: Permission denied”

The cron command is as follows :-

lynx -dump http://myurl.com/cgi-bin/autoresponder/activate.cgi

What it does is to log in toe activate.cgi at certain time of the day. By typing the url manually will require a password first and the command is executed.

Is this the problem that cause the permission denied ? If this is the case – how can i incorporate the password in the cron command line ?

Hope you can assist.
Thanks.

Reply

48 Shashi February 28, 2008 at 4:34 pm

What is the meaning of this?

30 1 * * * /home/clean_parse_logs.sh >> /home/logs/clean_parse_logs.log 2>&1

Reply

49 vijay September 30, 2010 at 5:23 am

it means at 1:30 morning, the clean_parse_logs.sh script starts running everday automatically and creates a clean_parse_logs in “/home/logs/” and then adds the information status of runing script “clean_parse_logs.sh” into the file “clean_parse_logs.log”.

Reply

50 thegetpr March 12, 2008 at 12:51 pm

how i can start a crownjo for a life time
very minute every second every day, week ,month and year

Reply

51 venki March 12, 2008 at 1:55 pm

i can’t say abt seconds.
* * * * * script

this will run the script for every min,hour,day,month,year.

Reply

52 rogier March 13, 2008 at 10:13 pm

Hi there,

I want to execute a php file on my webserver (non-unix). I do have a unix server and I want to execute Insert.php on my non-unix server from my unix server.

Is that possible?
What do I exectly need to type?
And is it possible to give an URL instead of a normal Path?

thanx,

Rogier

Reply

53 thegetpr March 20, 2008 at 10:34 pm

my crown job is working fine ***** script
but its execution time is very slow, how should i make it fast to work

Reply

54 Nilesh March 21, 2008 at 1:34 am

Use fcron; which doesn’t wake up every minute to see whether there is a job to be executed. It sees the next time when to wake up and wakes up at the particular time only unless a user edited his fcrontab to wake it up before. It saves resources. The syntax is quite similar but there is some difference which can be learnt by using.

http://fcron.free.fr

it is available in fedora’s repos.

Reply

55 pravin March 31, 2008 at 11:16 am

how do i append new task or crontab job using scprite in existing task

Reply

56 Rajitha May 13, 2008 at 6:52 am

submitting the job in crontab is a bit confusing for the beginners.

in a text file(eg., file.txt) give all the cron jobs you want to schedule
eg., 15 14 * * * /root/dir/script.sh

and submit the file using crontab
crontab file.txt

in order to do this user need to have permisson, which can be seen using cron.allow file

if the crontab file is already existing use crontab -e to add ur job to the crontab.
if it is already existing crontab -l displays the existing jobs

one imp thing to remember is you need to provide all absolute paths in the script which u want to schedule, otherwise u will end up in thinking why my cron job is not running though it is added properly.

Reply

57 Diego March 9, 2011 at 5:25 pm

wow, u r the first one in giving basics steps in how to do that. Thaaaaaank uuuu, not all people are geniuses here!!!

Reply

58 pushp August 23, 2013 at 8:29 am

nice really helpful.i got it.thanks

Reply

59 Hans May 15, 2008 at 9:28 pm

Nice tutorial,

To be complete it would be nice to mention:
/etc/cron.daily
/etc/cron.hourly
/etc/cron.deny
/etc/cron.monthly
/etc/cron.weekly
/etc/cron.d

As these are preferred afair

Reply

60 nixCraft May 16, 2008 at 1:05 pm

Hans,

The faq has been updated.

Reply

61 lalit June 20, 2008 at 6:41 am

Hi
I’m new in solaris.I want to create a cron job to delete a temp file in a directory and it run on every saturday of the week.

I have created a cron job as cron.txt.
0 12 19 6 4 rm /temp/*
Where will upload it?
How to run it?
.

Reply

62 Rafiuddin July 29, 2008 at 10:37 am

To remove or erase all crontab jobs
command:# crontab -r

Instead of -e as mentioned in the tutorial……

Reply

63 nixCraft July 29, 2008 at 11:32 am

Rafiuddin,

Thanks for the heads up. The faq has been updated.

Reply

64 Amjad August 23, 2008 at 12:26 pm

Thank You aLot, It’s help full answer

Reply

65 rptirore September 23, 2008 at 5:53 am

good one!

Reply

66 Rupo October 7, 2008 at 8:54 am

Is it possible to set up cron so that once it started, it will run 7 minutes later, then 3 minutes later, and then 7 minutes later i.e. running twice every 10 minutes

Reply

67 Ben November 25, 2008 at 2:35 am

Is the eight special string suitable use for all type/version of linux operating system? (eg.Red-hat, Ubuntu)

Example:
Special string Meaning
@reboot Run once, at startup.
@yearly Run once a year, “0 0 1 1 *”.
@annually (same as @yearly)
@monthly Run once a month, “0 0 1 * *”.
@weekly Run once a week, “0 0 * * 0″.
@daily Run once a day, “0 0 * * *”.
@midnight (same as @daily)
@hourly Run once an hour, “0 * * * *”.

Reply

68 nixCraft November 25, 2008 at 6:38 am

Ben

Yes, they works with Linux / UNIX as long as your are using Paul Vixie’s crond.

Reply

69 Ben November 25, 2008 at 9:43 am

Thank you a lot. it is help me a lot.

Reply

70 Subeesh December 9, 2008 at 8:12 am

Hi,
I want to run a script – everyday 12:00 am – 01:00 pm every 5 minutes,
Please help me
Thanks,
Subeesh

Reply

71 vawani December 8, 2011 at 9:33 pm

*/5 00-13 * * *

Reply

72 karthikesan December 12, 2008 at 3:02 pm

Hi
I want to run hourly job.
The script :
$userp=`du -cskh /path/ |sed -e ‘G//g’`
ALERT=90
$st=echo”if($userp > $ALERT) 1 |bc ”

when i run this .The cron is giving me a error like use test and at this line iam getting error
like teletype (u can’t use this option -c -h).
1)crontabs -e
2)Cronjob
********
5 * * * * /path/scripts
Please help me
Thank
kathi

Reply

73 Nayibe December 16, 2008 at 6:42 pm

I need to set up a cron that runs a script every other Friday.

Reply

74 Harrel January 2, 2009 at 9:27 am

I want to add a cronjob or the following cron command

/usr/bin/php -f /homepages/33/d249180215/htdocs/iem/admin/cron/cron.php

I entered
*****/usr/bin/php -f /homepages/33/d249180215/htdocs/iem/admin/cron/cron.php

in ssh via putty
but it’s giving error like pattern not found: usr

Can anyone help? I use 1and1 hosting.

Reply

75 Ramit January 9, 2009 at 12:19 am

This is not working. What is wrong
MAILTO=”4085298665@txt.att.net”
0 3 * * * /root/backup.sh >/dev/null 2>&1

Reply

76 swati February 20, 2013 at 12:31 pm

you are using both one to mail the response the first line of the code and on the other hand >/dev/null 2>&1 means stopping the output to forward as mail . use either of them.

Reply

77 SHEETAL.A January 9, 2009 at 5:24 am

hi,

I want to use cron job for backups. I am using suselinux 9.0

Reply

78 googleguy February 21, 2009 at 5:44 pm

Well
3**** /path/to/command
means to run command every 3rd minute of every hour not every 3 mins ……..
understand this diff………to make it run every 3mins we have to do
*/3****/path/to/command
And to add php file to crontab add #!/usr/bin/php //this in to php file
and also to crontab file .(property of file and folder shd be rwx );

Reply

79 Download Free Photos February 24, 2009 at 12:05 pm

Many thanks, it’s help me a lot.

Reply

80 amit March 25, 2009 at 9:21 am

Hi,
I put following in a file named ‘cronjob’ in the /etc/cron.d
*/5 * * * * root /etc/cron.d/script.sh >> /opt/cronjobs/cron.log
but dont see any thing happening. Pls suggest
Thanks

Reply

81 maaly March 26, 2009 at 9:15 pm

write echo command that print “hello” message on o
every day at a 2 am at the morning for the first week of the month

Reply

82 Subeesh April 2, 2009 at 6:27 am

Hi all,
I want to write cron to run a script from 12 noon to 11:30 pm, every 5 minutes
I have written like this, which I guess, it works from 12 noon to 11 PM only,
0-55/5 12-23 * * * /path/to/command
but how should I re-write it to run the script from 12 noon to 11:30 pm, every 5 minutes ?
Thanks in advance,
Subeesh

Reply

83 Haid Avila April 22, 2009 at 2:28 am

Hi, I´ve just made my script and put it into crontab…
I want my script to run this command ( opensipsctl fifo lb_resize 1 pstn 0) if ping fails.
It looks like this…

#!/bin/bash
# add ip / hostname separated by while space
HOSTS="192.168.0.11"
# no ping request
COUNT=1
 for myHost in $HOSTS
do
  count=$(ping -c $COUNT $myHost | grep 'received' | awk -F',' '{ print $2 }' | awk '{ print $1 }')
  if [ $count -eq 0 ]; then
    # 100% failed
    opensipsctl fifo lb_resize 1 pstn 0
  fi
done

If I run the script from the command line it works nice and smooth, but if it runs from the CRON it doesn´t work

I have this on my crontab so it will run every minute

0-59 0-23 * * * /etc/opensips/monitor_server1.sh

If I look at my LOG, my CRON call it
Apr 21 21:25:01 [cron] (root) CMD (/etc/opensips/monitor_server1.sh )

But it doesn´t work…

Any idea?
Regards!

Reply

84 nixCraft April 22, 2009 at 6:21 am

Use full path names in cron jobs.

Reply

85 Dhruv Patel October 13, 2011 at 7:28 am

For every minute use * * * * * /etc/opensips/monitor_server1.sh

Reply

86 Haid Avila April 22, 2009 at 5:47 pm

Thanks for your advise Vivek

Regards!

Reply

87 Russell May 22, 2009 at 2:30 am

Question, I’m running UBUNTU 9.04 and when it start up it checks and set the time only ounce, I need a cron job that will check and set the time hourly as long as the program is running. And to say that I don’t know what I doing is a understatement. I’m trying to get this mailserver to keep correct time. Thanks for the help. Russell

Reply

88 dinesh June 2, 2009 at 10:31 am

hi
i wnt to know how i can schedule backup though crontab.
please send a particular script to me on my {snip_no_email_ids}

Reply

89 dinesh kumar midha June 2, 2009 at 10:40 am

i hv used hints for tunning (max hints was orders )
now i m running the report but it is not work
ora-01652 unable to extend temp segment by 128 in tablespace temp

i have added new datafile or resize also but it is not working
if u hv any idea plz give the solution

Reply

90 MsfStl June 16, 2009 at 2:41 pm

I have a cron job with multiple jobs listed at various times throughout the day.

I have two questions:

1) For each job, is it possible to reset the MAILTO statement to a different user? (E.g., Cathy is a user for a cron job that runs at 11:30 PM every day, her cron job is:
30 23 * * * /usr/local/bin/sas -noterminal /users/adrc/cathy/imaging/makedata.sas &
Scot is a user of a cron job that runs at 2:39 AM every day, his cron job is:
13 2 * * * /usr/local/bin/sas -noterminal -sysin /users/adrc/scot/sas_program
s/batch_scripts/hpdabat.sas & )
So is it possible to set a MAILTO= Cathy@domain.com prior to her cron job and then set another MAILTO=Scot@domain.com for his cron job?

2)While my cron jobs work, I have been receiving the following failed message:
/bin/sh:
: command not found

Any ideas what could be causing this?

Thanks for your time.

Reply

91 nixCraft June 16, 2009 at 3:16 pm

1) For each MAILTO add cronjob to users account and not to root users account. Run:

crontab -e -u cathy

2) /bin/sh is not installed hence you see the error. A

Reply

92 amol June 21, 2009 at 4:53 am

I have added following script to crontab , but it fails to execute at Schedule time

00 0,2,4,6,8,10,12,14,16,18,20,22 * * * [ -x /usr/local/SAN/rcomsapp40db/rcomsapp40db] && /usr/local/SAN/rcomsapp40db/rcomsapp40db

Other scripts/cronjobs with same syntax are working fine.

Any ideas what could be causing this?

Reply

93 MsfStl June 22, 2009 at 2:02 pm

Thank you, Vivek.

I now have the Mailto working.

However, now instead of the fail message “: command not found”, I get a null fail message. Basically, it’s just an email stating the cron job failed, but nothing in the message. Just blank.

I appreciate any help in correcting this.

Thanks,

Scot

Reply

94 nixCraft June 22, 2009 at 3:03 pm

Make sure you have correct PATH settings set for your contab. Also, use full path when run jobs via crons.

Reply

95 MsfStl June 22, 2009 at 3:15 pm

Thanks again Vivek. I believe I found out what was going on. I had the following job scheduled:

17 2 * * * /usr/local/bin/sas -noterminal -sysin /users/adrc/scot/sas_programs/batch_scripts/hpdabat.sas 2>&1 | mail -s “RE: Scot HPDA Cron Fail” scot@xxxxxx.edu

What was happening (and this is where my inexperience comes in) is that the code “2>&1 | mail – s….” was set to send an email everytime the job ran with the subject line ” RE: Scot HPDA Cron Fail”. I was piping that to run everytime (I thought it would only send if it failed.) The “2>&1″ code basically states that the email include a standard error message, if there is one, along with any other message. Since there was no error message the code did what I told it to and sent me an email called “RE:Scot HPDA Cron Fail” with nothing in it. The job works as it should. I have decided to remove the mail code and just let it do it’s thing.

Thanks again,

Scot

Reply

96 nixCraft June 22, 2009 at 3:38 pm

Good.

Or you can add mailing code in your script itself:

[ $? -ne 0 ] && mail -S “blah” blah@exampl.com

Reply

97 Rituparna June 23, 2009 at 9:13 am

Hi
I ‘m trying to schedule a batch job that will show the disk space occupied of my present working directory at every 15 minutes daily from 2:15pm for the month of June and the output will be mailed to my email id.

the script is as follows

crontab -e

15 14 6 * * //df -h

saving the file with myfile.txt and then when i type crontab myfile.txt an error comes up saying
“myfile.txt”:1: bad minute
errors in crontab file, can’t install.

Reply

98 Rituparna June 23, 2009 at 9:15 am

just a bit of modification to the above
it is 15 14 6 * * //df -h

Reply

99 Rituparna June 23, 2009 at 9:17 am

just a bit of modification to it
15 14 6 * * //df -h

Reply

100 Narendra June 29, 2009 at 5:52 am

Hi,
How can we call php page from CRONTAB in every 5 seconds. I had used this by using sleep funtion with some logic. Script executes for a time and sleeps for 5 seconds for 10 times within 1 minute interval. But the problem occurred is sever gets too busy when I called crontab file like this.
So I would like to know how can file be executed in every 5 seconds without any problem?

Reply

101 nami June 30, 2009 at 5:27 am

does all the files in /etc/cron.daily folder on a daily basis.
Actually i have copied a sh file in this folder yesterday but it did not get executed .
As if this file is executed one of my tables in the database gets updated.
I am not sure whats going wrong

Reply

102 nami June 30, 2009 at 7:21 am

According to this link the files under /etc/cron.daily should get executed….
But in my case its not getting executed
i used putty to copy the file from one of the directories in the system to the /etc/cron.daily directory….
Would some permissions be causing it to not execute it.
http://www.debian-administration.org/articles/56

Reply

103 nam June 30, 2009 at 8:16 am

This link specifies all the files under this directory will be executed daily…
http://www.debian-administration.org/articles/56
But in my case it is not executing is it some permission issue
my crontab file looks like below :

//////crontab////////////////
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly

//////crontab////////////////

There is no cron.allow file.The cron.deny file does not contain anything.

Reply

104 Ben July 30, 2009 at 2:00 am

hi,
if i put both cronjob in crontab which one will run first?

eg:
@yearly Run once a year. 0 0 1 1 * /path/to/command
and
@monthly Run once a month. 0 0 1 * * /path/to/command

Reply

105 Aditya September 14, 2009 at 1:12 pm

Hi i have to run a Command in eyery minute Command is hwclock –hctosys , how i can make entry in Crontab ,m is a new for Crontab ,Please Help me …….mine mail id is

Reply

106 Sunil September 27, 2009 at 11:47 am

Hi,
Please let me know how to make a cron entry for this scenario:-

A task should be executed at 1st month of every quarter and on every Sunday at 10:30 am.

Thanks in Advance…

Reply

107 Guiscard October 29, 2009 at 5:16 am

Hello, I m using a linux server, and I’d to know if anyone knows a script that can clear the
/tmp/ dir every 1 hour.

I am currently doing manually. The directory gets full every few hours due to too many activities on the server.

I currently run the following:

rm -rf /tmp/*

what can i do to automate that?
Thank you – Guiscard

Reply

108 srinivashan November 10, 2009 at 12:06 pm

hai gays ,
i am a new bee to linux and i am using fedora 11 and i want to take a backup
files daily so anyone help mee plzzz
how to create cronjob and with commands
for exp: i have a file in /root/desktop/srinnivas and i want to save it to another plc like
my mail id is cnus01@gmail.com plz hlp

Reply

109 srinivashan November 10, 2009 at 12:08 pm

in /root/backup

my mail id is cnus01@gmail.com plz hlp

Reply

110 srinivashan November 10, 2009 at 12:32 pm

hai gays

i want to run this cammand daily ( cp /root/desktop/123.flk /root/srinivas/imp files/ )
using corn jobs or is there any other way to run this command daily automaticaly
plz hlp me anyone

thanks srinivas

Reply

111 Jade November 14, 2009 at 2:33 am

Wonderful article. Thanks!

Reply

112 map007 November 20, 2009 at 7:06 am

Hi,

I want to run cron job in every 20 second, so i have created following script.

#!/bin/bash
while true
do
/usr/bin/php -q /home/abc/public_html/Cron.php &
pid=$!
sleep 20
kill -SIGKILL $pid
done

But its not working…. Please guide me if i m wrong……….

Thank you.

Reply

113 Ducky November 25, 2009 at 10:06 pm

I am new to CRON command. What I want is to have a CRON job execute myWeb Service which takes two parameters. Maybe I should use a .sh file instead of the whole URL with parameters in the command line. Can someone give me a simple sample, thank you.

Reply

114 Ani November 27, 2009 at 4:44 am

Hai,

How to send a request to a webserver all times when i power on my system(fedora) automatically to indicate im online?

Reply

115 Ramakrishnan December 3, 2009 at 6:31 am

Hi,
how to create cron job for running klinkstatus link checker for daily that must send html format output from klinkstatus to a emailaddress.
How to create it?

Thanks
Ramakrishnan t

Reply

116 anil December 4, 2009 at 9:45 pm

HI,
I am using cron jobs.It is working fine.It fetches some links and stores in database. But the problem is when i first run the cron it has fetched 5,000 links per hour.After that it is very slow.Now not even fetching 100 links per hour.What can i od to improve?

Reply

117 Russty December 23, 2009 at 4:12 pm

I need to know how to make a script run every 20 minutes.

Reply

118 Raj January 2, 2010 at 8:32 am

Guys,

I want the following to run every 1 hour. Can you please tell me what to do?

tmpwatch –mtime –all 144 /tmp

Reply

119 Noori February 9, 2010 at 2:15 am

1. Immediately after installing a new server one of the things you should do is document exactly what files are suid. As part of your job monitoring a server you will periodically look at what files on the server are suid. A file suddenly becoming suid when it was not originally is a sign that your server has been compromised. What UNIX command will list all files that are suid on the server? What UNIX command will list all files that are sgid on the server?

2. Write a bash script which could be scheduled in cron to run nightly. The script would execute the two UNIX commands from step 1 above. If there is a difference between the original file (listing the suid files on the server) that you created when you installed the server and the file generated when you ran the cron job then you must email the administrator with the details of the differences. If the suid files on the server have not changed, do nothing.

Can someone Please help me solve the above two task. I kindly appreciate.
Thank You
Noorii

Reply

120 Ganesh April 1, 2010 at 7:59 am

Hi,

I want to run my SAS code everyday at 4:30pm on unix server. can any one help me in creating a cornjob ?

Thanks

Reply

121 siva April 28, 2010 at 1:21 pm

how to schedule a job with time 08:45:30 am every day and every month?

Reply

122 siva April 28, 2010 at 1:34 pm

how to display which are modified time(mtime) between 5 t0 10 days in unix?

Reply

123 sss April 28, 2010 at 1:50 pm

how to display which are modified time(mtime) between 5 t0 10 days in unix?

Reply

124 Naseer May 19, 2010 at 6:29 am

how to turn on system automatically while system is in turn off state

Reply

125 johnny June 8, 2010 at 8:58 am

helllo…
i have problem about my server elastix…
i configure crondtab for automatic reboot
but my mechine cannot reboot time i set.
how to solve..
help me…….
thanks

Reply

126 Anonymous June 11, 2010 at 11:14 am

Hi,

Can anyone tell me how to set jobs in cron tab

Reply

127 Anonymous June 11, 2010 at 11:15 am

Kishore,

Can anyone tell me how to run pl/sql jobs in unix.

Reply

128 Santiago June 14, 2010 at 3:57 am

below script is not running on linux, the /bin/sh has been defined in the $PATH. Kindly advise ?

=======================================
#!/bin/sh

export INFORMIXDIR=/opt/informix/11.50.FC6
export INFORMIXSERVER=czchols1790_1_soc
export ONCONFIG=onconfig_1
export PATH=$INFORMIXDIR/bin:$PATH
export TERMCAP=$INFORMIXDIR/etc/termcap

dbaccess gcdb < bash

Reply

129 Arps June 17, 2010 at 6:22 am

Hi,
i want to create a cron job to check the no of filehandler every hour in my application. can anyone help me

Reply

130 nany June 21, 2010 at 5:58 am

I set my command at
45 01 * * * /PullMissingFiles/GeneralScripts/GenericPullFilesScript.sh
the script is running for yesterday
MONTH=`TZ=CST+24 date +%m`
DAY=`TZ=CST+24 date +%d`
YEAR=`TZ=CST+24 date +20%y`

if [ “${#DAY}” -eq 1 ]
then
DAY=”0$DAY”
fi

yesterday=$YEAR$MONTH$DAY

but the result is pulling for 2days ago (e.g. if today is 21 we will got the result of 19th)

?????please help me

Reply

131 MSK July 27, 2010 at 11:10 am

I want to schedule a job which will execute only once in life time. Is it possible to schedule it using cronjob.
Please suggest.

Reply

132 Brian July 28, 2010 at 7:51 am

it could be nice if you could write HOW you append in this so-called-editor that crontab is using….

Reply

133 vamsi krishna August 18, 2010 at 3:20 pm

hey .,i have few questions

1)how can i append to the existing crontab file of root with automation?
like when i give as root –> crontab /var/shell.sh.everythin previously present is getting vanished.?help me

2)In the end i need to remove this entry at the time of uninstallation of my system?
Thx in advance :)

Reply

134 gaurab August 20, 2010 at 7:20 am

How to set the cron job that runs every week on sunday 10 am.
10 * * * 1/path/to/command
Is the above one correct.Please guide me.

Reply

135 gese74 October 5, 2010 at 5:04 pm

Hello Gaurab,

From your command
10 = tenth minute
* = every hour
* = every day
* = Every month
1 = Monday
So since you have Monday it automatically nullifies the every day.

So for your request the best should be
00 10 * * 0 or 7

I hope this helps

Reply

136 vamsi krishna August 20, 2010 at 9:10 am

0 22 * * 0 path od the script to be executed

Reply

137 bobb September 2, 2010 at 3:23 pm

HI all
i had to run java exe and wanted to add entry in crontab.
crontab entry
23 20 * * * /home/testing/CSS/Run_Alerts.sh

cat Run_Alerts.sh
#!/bin/sh
cd /home/testing/CSS/
nohup java css_main
still cron is not working,
-rwxrwxrwx 1 testing testing 58 Sep 1 20:21 Run_Alerts.sh

please advise

Reply

138 vamsi krishna September 3, 2010 at 5:21 am

hey check whether cron service is up and running .

If thats up then check ur jdk version .First try to keep some echo statements in ur cron tab and try to write to a file .then u can ensure dat cron is working properly .

then u can keep ur own commands and try..ALL da best

Reply

139 Ali Mabrook September 8, 2010 at 6:35 am

sometimes it shows errors

Reply

140 g September 9, 2010 at 7:10 am

is my SH file is having mistake?
take alook…
[quote]
#!/bin/sh
tarikh=””$(date +%F_%R);
nama=”crm_”;
fileHasil=””$nama$tarikh.tar.bz;
targetLoc=”/usr/share/serverware/backup/”;
targetWeb=”/var/www/crm/”;
echo “Processing Backup for $tarikh”;
echo “Backing up in progress…”;
tar cvjf $targetLoc$fileHasil $targetWeb;
echo “Backed up Success! Saved on $targetLoc$fileHasil”;
[/quote]

I could execute it manually,but once I use it at CRONTAB
it never executed … why eh?
anyone have experienced about this before?

Reply

141 Reddy September 16, 2010 at 1:38 pm

Hi,

i need to set up a corn job from Linux server to HP server,
Is it possible to set up the corn job from one server to another server without script.
Please advise

Reply

142 Nicole January 7, 2011 at 3:58 am

Hi, could you please help me create a cron job (in php) that will check disk space every day and will send me email if it’s 75% full, and will not send me an email if it’s not.

Thank you so much! i’m a new bie.

Reply

143 Anbu January 14, 2011 at 8:46 am

I want to kill the jboss server and restart the jboss server in linux machine.
Please provide the solution

Reply

144 a12345 February 21, 2011 at 9:16 am

Hi all,

I want to run a particular script say a.sh daily at some particular time…
Is it fine if I place the script which i have to run(a.sh) in cron.daily directory???
or
Do I have to edit crontab???

Please help me out!!!

Thanks in advance!

Reply

145 nixCraft February 21, 2011 at 10:16 am

Yes, place your script in /etc/cron.daily/ so that it will get run once a day. If you need to run the script, say at particular time (6 pm everyday), than add it to user crontab.

Reply

146 ramaraj ponnan March 3, 2011 at 8:10 am

Hi,
I need a cron job .
if the username and password is wrong while entering into any application, it should
generate a mail to some mail ids, every after 20 sec of logging (error logging)

Reply

147 Shuja Ali March 7, 2011 at 5:56 pm

Hi,

I have a cronjob that runs as follows:
PATH=/usr/bin:/bin:/usr/local/mysql/bin:/opt/TKLCixp/prod/db/utils/sql
22 17 * * * /home/cfguser/housekeeping/Daily_Scripts/Sessions.sh >/dev/null 2>&1

When the script runs it runs a .sql file located in directory “/opt/TKLCixp/prod/db/utils/sql” and the error message from mail is shown below:
From cfguser@ixp0001-1a Mon Mar 7 16:46:01 2011
Date: Mon, 7 Mar 2011 16:46:01 GMT
From: root@ixp0001-1a (Cron Daemon)
To: cfguser@ixp0001-1a
Subject: Cron /home/cfguser/housekeeping/Daily_Scripts/Sessions.sh
X-Cron-Env:
X-Cron-Env:
X-Cron-Env:
X-Cron-Env:
X-Cron-Env:

sqlplus: error while loading shared libraries: libsqlplus.so: cannot open shared object file: No such file or directory

When the script is run from commandline it is fine, but cron fails with above error. I suspect its something to do with environment variables. Is it something I should add to my cron or script to declare which directories it should include when running.

Br,
Shuja

Reply

148 Rao March 23, 2011 at 12:20 am

Hello,
I have running cron job for a while now but now recently at my work they changed the mail server to a different smtp server. How do I update the new SMTP server. I really appreciate any help…!

Thanks
RG

Reply

149 Naraen Sridharan March 28, 2011 at 5:22 am

Guys,

“—– Day of week (0 – 7) (Sunday=0 or 7)” This line in the post is wrong. Its always 0-6 and never 7. If you use 7 the whole crontab file cannot be parsed by its parser.

Thanks,
Naraen

Reply

150 Krushna April 12, 2011 at 3:59 am

HI,

I want to run a 2 line shell script in crontab .If i run the script from konsole, its working fine. In crontab, its not working.The very first line is executing but not the second line. The script contains
chown x.x /source/ -R
sudo -u x rsync -azvH –remove-source-files /source/ x@:/destin/

(private key and pub key added in source and destination, no need of authentication for user x )
please advise me.

cronntab entry is :-
*/30 * * * * /path/rsync.sh >> /path/rsync.log

Reply

151 Rohit May 16, 2011 at 9:56 am

Hi,
I am a newbie to linux. I wanted a shell script to run every 2 minutes.So i wrote the following in my crontab:
2 * * * * /path to script
What do i have to do next to make sure that the cron is running? Because i see that the job is not running.Can you please help?

Reply

152 Amode May 24, 2011 at 10:36 pm

What you need here for this command to run is just this:
*/2 * * * * command
hope this will help good luck.

Reply

153 Dhinesh May 25, 2011 at 9:17 am

Is Crontab is only used for scheduling the scripts only?

Reply

154 fawaz June 10, 2011 at 10:28 am

I have this message coming up any time I want to run crontab,”No crontab for root”. This is despite the fact that all my cron commands and files are owned by root. I am using RHEL 5.5 X 86_64 version of linux. Any help. please?

Reply

155 MrCompTech July 4, 2011 at 6:02 pm

i have a script ‘awstats-mrcomptech.com’ in the /etc/cron.hourly with the permissions 744, it is owned by root/root but it is not running, It did run at one time, so I must have inadvertently changed something, but I can’t see what I did to cause this hourly cron jobs to not run!

how are the hourly cron jobs in ‘/etc/cron.hourly’ triggered to run?

I can manually run the script with ‘/etc/cron.hourly/awstats-mrcomptech.com’ and it executes just fine.

This is causing a problem that if I am not available to manually run the script at least once per day then the awstats for that day show 0 visits even though the apache log file show over a hundred visits.

Reply

156 MrCompTech July 4, 2011 at 6:10 pm

I found another post on the web that says a blank line is needed at the end of the script ‘awstats-mrcomptech.com’, I added the blank line and will now wait 52 minutes to see if it runs. i did edit that file so hopefully this will fix the problem!

Reply

157 MrCompTech July 4, 2011 at 7:14 pm

Yes, that did the trick, have to have a blank line for the last line of my cron file!

Reply

158 Lexyz August 4, 2011 at 10:40 am

Can someone explain to me what this script will do?

PATH-TO-PHP -q FULL-LOCAL-PATH-TO-DOMAIN/cron.php

Reply

159 MrCompTech August 5, 2011 at 2:49 pm

It will run whatever is in the PHP script named ‘cron.php’. Since it’s named ‘cron’ and is associated with a domain and I’m assuming that the ‘domain’ is website, this script will probably doing something such as running an autoresponder, making a backup of the website or backing up the MySQL database for the website.

Without the script it is impossible to provide specific details.

If you would like more detailed information about this script you can send me a copy using the form on my website at http://mrcomptech.com/index.php/ask-a-technology-question.

Reply

160 Lexyz August 5, 2011 at 3:22 pm

HI,

I still not get what this cron job means, PATH-TO-PHP -q FULL-LOCAL-PATH-TO-DOMAIN/cron.php

I have a site…and a cron.php was located here: http://www.mysite.com/cron.php

And I dont know how to configure the cron job code.

Using the code, PATH-TO-PHP -q FULL-LOCAL-PATH-TO-DOMAIN/cron.php

Where PATH-TO-PHP is the local path on your server to php and FULL-LOCAL-PATH-TO-DOMAIN is the full local path on your server to where you have the script installed.

so, using my site…. what will i put to replace PATH-TO-PHP and FULL-LOCAL-PATH-TO-DOMAIN

or…can you put here example?

please help. Thanks..

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161 MrCompTech August 5, 2011 at 4:37 pm

Hi Lexyz,

The instructions you received for using the script are generic. They have to be because the programmer cannot know on what server OS (Windows/Linux) or what version of the OS you will be putting the script on.

Are you using purchased web hosting services for your website? If so then depending on your hosting provider you maybe able to use your cPanel to add the cron job. Most hosting providers also include ‘How-To’ video tutorials for their customers. These are usually located near the top of the cPanel.

If the video tutorials are not sufficient then most likely you will have to contact your web hosting provider.

If you host your own server or have purchased a VPS (Virtual Private Server) then I may be able to help you more. For example PHP is usually installed in ‘/usr/bin/php’. On your own server or VPS you must have root access to setup this cron job. But if it’s not your server then you most likely do not have ‘root’ access and that is why you would need to get instructions from your hosting provider on how they have configured their servers and whether or not they allow you to add a cron job.

If I were adding this to one of my hosted web sites I would try to use the ‘Cron Jobs’ module in the cPanel to add the command to the list of commands as:

php -q /publichtml/cron.php

This may or may not work. My hosting provider does not provide a video on How-To setup a cron job so if this didn’t work I would have to contact my hosting provider for instructions.

On my own server for my website http;//mrcomptech.com and assuming the file cron.php were in the root of my website and assuming I wanted this command to run once every hour..

In the directory /etc/cron.hourly/

I would create the file named ‘mysite.com.cron.php’ (the name is arbitrary)
and this file would contain these 3 lines:

#!/bin/bash
/usr/bin/php /var/www/clients/client1/web1/web/cron.php > /dev/null
exit 0

Note there is a space after ‘/usr/bin/php’.
The file permission would need to be 744 so that the system can execute it.
To test that it worked, at the command prompt, I would run the command

/usr/bin/php /var/www/clients/client1/web1/web/cron.php

and then check to see that what it was supposed to do, it did. The script ‘cron.php’ is not a standard script, it is not something that is part of every website. So I can’t tell you specifically what your script is supposed to do without the script and any other scripts to which it it refers.

Have A Nice Day! (HAND!)

Reply

162 Lexyz August 5, 2011 at 4:42 pm

Thanks for the help.

I will check this out.

Great!

Reply

163 MrCompTech August 5, 2011 at 4:47 pm

You welcome and if you or anyone has any computer/Internet/technology question I would be happy to answer them at http://mrcomptech.com/index.php/ask-a-technology-question

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164 Ashish September 7, 2011 at 8:17 am

Hi,
I would like to schedule a crontab entry for a SAP script which should run quarterly, after every three month on Saturday (any weekend) but just one Saturday of the month.

I thought of below entry to be added:

0 22 * 3,6,9,12 6

I doubt bcoz of *, this will run on every Saturday of third month, where as I want to run it just one Saturday of the third month.

Could you please help me to create an entry which fulfil above criteria.
Thanks

Reply

165 MrCompTech September 8, 2011 at 4:03 pm

@ Ashish
I haven’t tested this but I think this is what you want:
0 22 1-7 3,6,9,12 6
This should run at 22:00 (0 22) but only if it one of the first seven (1-7) days of months Mar, Jun, Sept, Dec (3,6,9,12) and then only if it is a Saturday (6).

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166 Anup September 15, 2011 at 5:34 pm

Hi,

I’m using VPS with cpx control panel in FREEBSD platform and have root access also thru UNIX command. I need to create a Cron Job schedule for user x to clear his inbox and Junk mail box every day by 3.00 am. How to do it. Also want to create a job for SENDMAIL to restart everyday by 3.15 am. Pls help

Anup

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167 Pete September 27, 2011 at 10:26 pm

Awesome article. Love your site, I always get excited to see this.

I *think* there might be a typo for sending emails to a custom address:
MAILTO=”vivek@nixcraft.in”
0 3 * * * /root/backup.sh >/dev/null 2>&1 (“2>&1″ seems to disable email).

I’m not 100% sure on that, but I couldn’t get emails delivered until I removed 2>&1.

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168 Paul Smith October 23, 2011 at 3:09 am

Finally a blog with some insight into cron jobs. I have a question about the email issues. I have a dedicated server (just learning how to manage) for my websites and host a few of my friends sites on it also. One of them has a cron job set using cPanel and it reads:
curl -A “Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6″ -s http://www.hissite.com/billing/coin_cron/invoices.php

However the emails get sent to my server address and not his domain address. I went into /etc/crontabs but if I change it to his address then all future cronjobs that I wanted to create would go there also, correct? Not what I want. How do I change it so he and any future clients emails will be sent to their domain? Sorry if this is confusing as I am just learning. Thanks in advance.
Paul

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169 Rubli November 18, 2011 at 10:27 am

Hi,

I have a weblgic server in solaries.I want to take the backup of the log files of my server after a particular period.How can i do that by using cron.

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170 thiyagi December 1, 2011 at 6:52 am

thanks, was useful..

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171 Bobby January 18, 2012 at 3:01 pm

I am trying to set up a cron job to create a daily mysql back up. I installed the job as follows:
crontab -e
05 10 * * * /usr/bin/mysqldump –all-databases -u root -p`*password` | gzip -c > /home/db_backup/database_`date +%a`.sql.gz
saved and closed the file
restarted cron daemon
The job will not run.

I verified the command works when run manually, but I am new to using cron. Any ideas?

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172 reena January 20, 2012 at 6:22 am

Hi i want to diplay a “Hiiiiii ” in evry minute by crontab.
So how to do that ? Please give me solution.
Its urgent as i hv no idea at all about cronjob

Reply

173 Muhammad Hammad Qadir January 20, 2012 at 8:05 am

Hi every on, I newbie too i want to get a buckup of a folder the file is saved in that folder, I want to know how i can compress that folder like tar and then that compresssed tar file stored on a sperate location by crontab and should done in a 1 day of the week.

Your comments will be appriciated.

Reply

174 avinash January 22, 2012 at 2:30 am

how to create a folder daily using cron job

Reply

175 kamesh March 29, 2012 at 1:23 pm

Will you create the same folder name every time and in which ath you have to create?

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176 avishay January 22, 2012 at 8:34 am

I added a cron job but it doesn’t work. crontab -l shows my script * * * * * /tmp/some_script

pgrep cron shows 1471.
thanks

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177 sandeep February 13, 2012 at 12:22 pm

may i know how to give cron for 20 seconds

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178 Amit G October 23, 2012 at 10:55 am

smallest resolution is 1min. Look at alternatives : Quartz scheduler

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179 kiran March 27, 2012 at 6:13 am

Hi,
Can any one help me.
i need a cron job to sync data from linux pc/folder to other linux pc folder.
how to add password of other pc in script file.
can any one help me?

Reply

180 vedagiri April 9, 2012 at 9:49 am

how i check whether the cron job running or not?pl any one help me

Reply

181 Mario April 24, 2012 at 3:53 pm

how do I Add a cron job to send a timestamp to a file in their home directory every minute.
is it
crontab -e
then
* * * * 1 /timestamp/home/user/Documents.

I’m don’t think this is right. can anyone help

Reply

182 rj2029x October 5, 2012 at 5:46 am

1 * * * * /timestamp/home/user/Documents

1st place = Minutes
2nd place= Hours
3rd place= Days
4th place= Months
5th place = Day of the Week

Reply

183 anonymous October 15, 2012 at 11:27 am

It should be: */1 * * * * /timestamp/home/user/Documents
as if you only do: 1 * * * * /timestamp/home/user/Documents it will do it the first minute of everyhour and not everyminute of the hour

Reply

184 Jamshed Ahmed Qambrani June 9, 2012 at 8:14 am

I’ve configured RMAN backups on daily basis like sundaay, monday, tuesday. these backup are place on PROD server. now i want a script which copy my daily rman backup to another server as , from source server A /u01/RMAN/backup/sunday to target server B /u02/RMAN/backup/09-June-2012 in current date format in which date backup was take place.

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185 Arjay Almanzor July 16, 2012 at 7:17 am

Can you please send me the example of Crontab script that will backup one folder or that can automatically generate report on internet.
also the steps how to do it.

thanks.

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186 Reddy March 4, 2013 at 2:02 am

Hi friends

One job scheduled to run on dally on the basis of receiving data from the upstream environment. My Issue is data had delay one day wat ll do?

waiting for reply
Reddy

Reply

187 Prabhakar Shelke April 4, 2013 at 6:01 am

Hi,

I have total 4 cron job, and these are just send reminder mail to customer, these are given below,

First Cron – every four month Second Cron – every four month and 7 days Third Cron – every four month and 14 days Fourth Cron – every four month and 21 days
Suggest me How can i set up these cron jobs,

Thanks Inadvance….

Regards,
Prabhakar Shelke.

Reply

188 Pavan May 15, 2013 at 6:24 am

Hi All,

I need to run the cronjob for every 15 days. the script should be executed on saturday and sunday at evening 8’o clock..

Please let me know

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189 Pankaj June 4, 2013 at 6:12 am

Hi…..
how to use special staring plz tell me any one.

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190 Debrup Bhattacharjee July 18, 2013 at 9:00 am

I want to run a cron job at 4 AM every morning to clear the /tmp folder on the server. How can I write this job?

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191 Debrup Bhattacharjee July 18, 2013 at 9:50 am

I want a add a cron job which would run at 3 AM every morning and delete all content in the /tmp folder. Can someone help me with that?

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192 Erik August 10, 2013 at 3:55 am

I was unable to run this command:

You also need to enable crond service via sys v / BSD init style system. Under RHEL / CentOS / Fedora, you need to use chkconfig (ntsysv) command to enable crond on boot:
# chekconfg crond on

I see you had a typo there, as well. I’m using Lubuntu and it sees no candidate for chkconfig

Reply

193 newbie August 23, 2013 at 1:32 pm

I have to change my job scheduler from cron jobs to TWS, what I have to check in scripts, to ensure, there goes no wrong on shifting from cron to TWS.

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194 babu October 3, 2013 at 7:33 pm

I tried to configure crontab -e
for 23 14 10 3 8 /bin/echo hello
in the etc. I am unable to get the output. can anyone provide answer/solution.

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195 pete January 29, 2014 at 10:33 am

can’t use space try /bin/echo hello or use a little script

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196 Asheesh Singh February 7, 2014 at 3:39 pm

Hello,
How to scheduled a cron which run on at interval of 1 day 2 hour 30 minutes?

i used this */30 */2 */1 * *
Is it right?
Please help.

Reply

197 mahesh March 21, 2014 at 4:53 am

Hi ..
Anyone can help me ..i want to recieve a mail if processes go down/ dumps/ if the CPU or memory usage exceeds configured threshold values. can i use cronjobs for this or any other alternatives are there ..please help me

Reply

198 Debrup March 21, 2014 at 9:19 am

Hi,

I am not too sure about cron jobs, but there are number of Freeware tools out there (such as NagiOS), which you can configure to do the monitoring of the hosts and send out alert notifications based on required conditions.

Reply

199 Jaison April 22, 2014 at 7:09 am

I wish to run this following command on my Linux prompt every hour:

/etc/init.d/symphoniad restart WebClient

I have a text file with this command and saved into the /etc/cron.hourly folder with name restartwebclient. Will this command get executed every hour? If yes, how do i verify it and if no, how do i get to execute this command line every one hour.

Kindly advise.
Jaison.

Reply

200 Nix Craft April 22, 2014 at 7:12 am

Check crond log in your /var/log/ directory. On a CentOS/RHEL/Fedora Linux log file name – /var/log/cron.

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201 cyprriot May 19, 2014 at 10:26 am

Hi,

I have a vps system and I have working some job under webmin panel. I need to some script to check application while its stoped or not. if its stopeed script should be restart application again. and timely periond check.

thank you

Reply

202 Abhilasha June 10, 2014 at 11:56 am

Hi,

I want to run a cronjob at 10:30 pm and 5:30 am everyday. Can you tell me how to go about it?

Thanks :).

Reply

203 sasi July 6, 2014 at 2:35 pm

try this below expression
30 5, 22 * * * /path/to/script.sh

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204 Nayelii August 9, 2014 at 10:42 am

Just got bit by this myself. My oipinon is that it’s not suitable for production systems to automatically do this. At least put a question to the user if they want this turned on.My main database runs on an Areca hardware card that autoscrubs a 16 disk RAID-10 but doesn’t get in the way. I have several replicant slaves that have just a pair of 1TB 7200RPM SATA drives because they are read only and don’t need massive performance on IO. They work just fine. Until the first sunday of the month. I don’t care about bit rot, the data is all reproduceable from the master anytime I need it. I can monitor the drives with smart and replace them as needed easily and cheaply.However, a batch job that takes 6 hours ran for 12 hours last night and every customer I had was bitching about how slow the system was. In general there’s a lot of smart stuff done with mdadm. This is NOT one of them. Scott Marlowe

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205 Tamirat August 20, 2014 at 5:47 pm

Thanks a lot for sharing this resource by putting shell=/bin/bash …I solved error generated by crone job for not knowing some of the command I used in the bash script many thanks

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206 Prashanta August 26, 2014 at 3:13 pm

I hava a file media.sh which I intend to run daily. On running ./media.sh , an excel file test.xlsx is generated. I need to mail the test.xlsx file daily. How can I achieve this using cron ?

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207 Theo September 22, 2014 at 7:13 pm

Hi al. Most interesting. I have 3 inkjet printers with CISS. And I have Mepis Linux (KDE). As I’m going away for a month I would like to print a file called ‘test-page’ on each printer once a week to keep the print heads nice. Is it possible to start my computer with a script and perform this? (I would have to set wake up permissions in the BIOS I think) . What would the script look like . I am total newbie to bash and cron etc. Many thanks in advance for any help/script/instructions you email me.

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208 avinash October 10, 2014 at 2:45 pm

hello,
nice tutorial..very helpfull,
i have a question..
how to schedule a cronjob on 3rd saturday of every mount?
please help me on this..
thankyou

Reply

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