I have a script named email_kill.sh which kills the EMAIlL engine process. See the below content:
For this script to execute every hour I made a cronjob:
But this not executing at the moment and I tried to look in mail and found killed i n logs.
Then I saw it is picking some different PID and killing it.
Please can someone help me. I need to set up a cron job to measure CPU usage, Disk I/O and memory usage over a period of 1 minute along with the number of users logged into the system. I also need to send it to another user besides myself every hour. Please can someone help me! Thanks. (4 Replies)
Dear Guru,
I have submitted some cronjobs that has been running for quite sometimes. However, today I counter some cronjob did not run. Can you please explain what causes this to happen. Any system setting that limit number of cronjob per minutes to be started, etc?
Thanks.
Kelly (1 Reply)
hi
iam new at unix.iam running a cronjob,which i want to run on the first day of every month at 1AM.this is what i have specified:
00 01 1 * *
is this corect? (1 Reply)
Hi,
I'm totally new to shell scripting. I need help in my crontab script. I'm trying to read some values from user (username, log file directory, server) and then use those value to create a crontab for log rotation after some interval of time.
creating crontabs manually isn't big deal.... (11 Replies)
Hi,
I want to schedule a script on daily basis in morning 8:00 A.M and 5:00 P.M , how can i achieve this, i want the parameter
0 ? * * *
what will be the second parameter in my case.
Regards (1 Reply)
hi everyone I'm newbie in this forum hope I can get some help here :)
I have a command in crontab that executed every 1 minute
sometime this command need more than 1 minute to finish
the problem is, the crontab execute this command although it's not finish processing yet and causing the system... (7 Replies)
Hi I am very new to linux. I want to run a cronjob every 15 minutes that checks a directory for files. If the directory contains more than ten files I want it to send an email to me.
All I have is this...
*/15 * * * * ls -l | wc -l | | mail -s "This is just a test"
I would... (2 Replies)
How to set cronjob for 48 hours.
I can set for 2 days as shown below.
* * */2 * *
It is creating confusion for 30 days & 31 days per month. (3 Replies)
Discussion started by: Nishit
3 Replies
LEARN ABOUT OSX
shlock
SHLOCK(1) BSD General Commands Manual SHLOCK(1)NAME
shlock -- create or verify a lock file for shell scripts
SYNOPSIS
shlock [-du] [-p PID] -f lockfile
DESCRIPTION
The shlock command can create or verify a lock file on behalf of a shell or other script program. When it attempts to create a lock file, if
one already exists, shlock verifies that it is or is not valid. If valid, shlock will exit with a non-zero exit code. If invalid, shlock
will remove the lock file, and create a new one.
shlock uses the link(2) system call to make the final target lock file, which is an atomic operation (i.e. "dot locking", so named for this
mechanism's original use for locking system mailboxes). It puts the process ID ("PID") from the command line into the requested lock file.
shlock verifies that an extant lock file is still valid by using kill(2) with a zero signal to check for the existence of the process that
holds the lock.
The -d option causes shlock to be verbose about what it is doing.
The -f argument with lockfile is always required.
The -p option with PID is given when the program is to create a lock file; when absent, shlock will simply check for the validity of the lock
file.
The -u option causes shlock to read and write the PID as a binary pid_t, instead of as ASCII, to be compatible with the locks created by
UUCP.
EXIT STATUS
A zero exit code indicates a valid lock file.
EXAMPLES
BOURNE SHELL
#!/bin/sh
lckfile=/tmp/foo.lock
if shlock -f ${lckfile} -p $$
then
# do what required the lock
rm ${lckfile}
else
echo Lock ${lckfile} already held by `cat ${lckfile}`
fi
C SHELL
#!/bin/csh -f
set lckfile=/tmp/foo.lock
shlock -f ${lckfile} -p $$
if ($status == 0) then
# do what required the lock
rm ${lckfile}
else
echo Lock ${lckfile} already held by `cat ${lckfile}`
endif
The examples assume that the file system where the lock file is to be created is writable by the user, and has space available.
HISTORY
shlock was written for the first Network News Transfer Protocol (NNTP) software distribution, released in March 1986. The algorithm was sug-
gested by Peter Honeyman, from work he did on HoneyDanBer UUCP.
AUTHORS
Erik E. Fair <fair@clock.org>
BUGS
Does not work on NFS or other network file system on different systems because the disparate systems have disjoint PID spaces.
Cannot handle the case where a lock file was not deleted, the process that created it has exited, and the system has created a new process
with the same PID as in the dead lock file. The lock file will appear to be valid even though the process is unrelated to the one that cre-
ated the lock in the first place. Always remove your lock files after you're done.
BSD June 29, 1997 BSD