10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Can crontab be removed from an AIX system. We had a script that was running on the system. It stopped working. An outside vendor said that crontab does not exist on the system. and that is why it is not running. How can i verify this and get it back on the systems if needed?
thanks (4 Replies)
Discussion started by: fierfek
4 Replies
2. Shell Programming and Scripting
Hi
I am trying to create a cron job but i get an error
I have 2 files my main shell script with html which is genWebsite.sh and another called config.sh which hold variables that I pass to genWebsite.sh by using the line ./source config.sh.
I want a cron job to refresh a html generated... (14 Replies)
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3. UNIX for Dummies Questions & Answers
hi,
i have to backup a database everyday on a Sun Microsystem.
i have been looking around and have found that crontab might be the answer.
the list of steps that have to be followed for me to get the database is:
1. on cmd telnet the equipment.
2. put the user name and password.
3. i... (20 Replies)
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4. Linux
Im setting up crontab to run a command at 0800
my current crontab entry is:
0 8 * * 1,2,3,4,5 tcpdump -s2000 -w'flowroute-%H%M.pcap' -G900 -W34
This should start the script at 800am monday through friday as i understand it.
I have tested this a couple times and it does not start as... (6 Replies)
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5. Linux
Hi!
I found this line in the root's crontab:
Who does "*/1" mean???
I have never met this case...
Thx (4 Replies)
Discussion started by: Castelior
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6. UNIX for Dummies Questions & Answers
That should echo Machine name and then the hostnames command into the test file every minute shouldnt it?
Cant seem to get it working. (4 Replies)
Discussion started by: RAFC_99
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7. Solaris
A job which schedule on every 1st day of the month in crontab is being removed after the job run. What is the possibility that crontab entry can be removed?
Pls advise. Thanks.
This is in sun solaris version 9. (1 Reply)
Discussion started by: KhawHL
1 Replies
8. UNIX for Dummies Questions & Answers
I am going to design the crontab..........
May I get some help.... (1 Reply)
Discussion started by: sathiyamoorthy
1 Replies
9. Shell Programming and Scripting
i wrote a shell script and put it in a crontab.
but the script is not working.
please help
thanks in advance (10 Replies)
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10. UNIX for Advanced & Expert Users
Dear friends,
sz command transfer files from unix to hyperterminal (in WINDOWS OS)
CRONTAB is used for jobs periodically
can we use sz command in the crontab in UNIX Operating systems ? If so plz guide me, as iam unable to put sz command in crontab
... (1 Reply)
Discussion started by: manikumar
1 Replies
CRONTAB(1) General Commands Manual CRONTAB(1)
NAME
crontab - maintain crontab files for individual users (Vixie Cron)
SYNOPSIS
crontab [ -u user ] file
crontab [ -u user ] [ -i ] { -e | -l | -r }
DESCRIPTION
crontab is the program used to install, deinstall or list the tables used to drive the cron(8) daemon in Vixie Cron. Each user can have
their own crontab, and though these are files in /var/spool/cron/crontabs, they are not intended to be edited directly.
If the /etc/cron.allow file exists, then you must be listed (one user per line) therein in order to be allowed to use this command. If the
/etc/cron.allow file does not exist but the /etc/cron.deny file does exist, then you must not be listed in the /etc/cron.deny file in order
to use this command.
If neither of these files exists, then depending on site-dependent configuration parameters, only the super user will be allowed to use
this command, or all users will be able to use this command.
If both files exist then /etc/cron.allow takes precedence. Which means that /etc/cron.deny is not considered and your user must be listed
in /etc/cron.allow in order to be able to use the crontab.
Regardless of the existance of any of these files, the root administrative user is always allowed to setup a crontab. For standard Debian
systems, all users may use this command.
If the -u option is given, it specifies the name of the user whose crontab is to be used (when listing) or modified (when editing). If this
option is not given, crontab examines "your" crontab, i.e., the crontab of the person executing the command. Note that su(8) can confuse
crontab and that if you are running inside of su(8) you should always use the -u option for safety's sake.
The first form of this command is used to install a new crontab from some named file or standard input if the pseudo-filename ``-'' is
given.
The -l option causes the current crontab to be displayed on standard output. See the note under DEBIAN SPECIFIC below.
The -r option causes the current crontab to be removed.
The -e option is used to edit the current crontab using the editor specified by the VISUAL or EDITOR environment variables. After you exit
from the editor, the modified crontab will be installed automatically. If neither of the environment variables is defined, then the default
editor /usr/bin/editor is used.
The -i option modifies the -r option to prompt the user for a 'y/Y' response before actually removing the crontab.
DEBIAN SPECIFIC
The "out-of-the-box" behaviour for crontab -l is to display the three line "DO NOT EDIT THIS FILE" header that is placed at the beginning
of the crontab when it is installed. The problem is that it makes the sequence
crontab -l | crontab -
non-idempotent -- you keep adding copies of the header. This causes pain to scripts that use sed to edit a crontab. Therefore, the default
behaviour of the -l option has been changed to not output such header. You may obtain the original behaviour by setting the environment
variable CRONTAB_NOHEADER to 'N', which will cause the crontab -l command to emit the extraneous header.
SEE ALSO
crontab(5), cron(8)
FILES
/etc/cron.allow
/etc/cron.deny
/var/spool/cron/crontabs
There is one file for each user's crontab under the /var/spool/cron/crontabs directory. Users are not allowed to edit the files under that
directory directly to ensure that only users allowed by the system to run periodic tasks can add them, and only syntactically correct
crontabs will be written there. This is enforced by having the directory writable only by the crontab group and configuring crontab com-
mand with the setgid bid set for that specific group.
STANDARDS
The crontab command conforms to IEEE Std1003.2-1992 (``POSIX''). This new command syntax differs from previous versions of Vixie Cron, as
well as from the classic SVR3 syntax.
DIAGNOSTICS
A fairly informative usage message appears if you run it with a bad command line.
cron requires that each entry in a crontab end in a newline character. If the last entry in a crontab is missing the newline, cron will
consider the crontab (at least partially) broken and refuse to install it.
AUTHOR
Paul Vixie <paul@vix.com> is the author of cron and original creator of this manual page. This page has also been modified for Debian by
Steve Greenland, Javier Fernandez-Sanguino and Christian Kastner.
4th Berkeley Distribution 19 April 2010 CRONTAB(1)