Either this or you create a semaphore file: consider the following script stub:
This makes sure the script runs only one instance at a time.
I hope this helps.
bakunin
Not quite. There is a race condition between the time the existence test ([ -e "$fSemaphore" ]) is executed and the time the semaphore file is created (touch "$fSemaphore") that can allow two or more copies of this code to run simultaneously and not realize that another invocation is running.
This can be worked around with the shell's do not clobber option:
Note that both of these run a risk of leaving the semaphore file in place if the script is terminated by a kill signal (for the code above) or by any signal (for the code bakunin suggested). If this happens, the semaphore file will have to be manually removed before the script will run again successfully.
I am in need of some help; think I have confused myself.
Here is the issue I am faced with.
The script log file was fine, the nohup.out file has tens of thousands of lines like illegal use of sleep: sleep seconds
So I assume there is something with the seconds calculation in the script... (1 Reply)
Hi All I have a requiremnt to run a script inside another script.
here i am pulling the record count from the table in oracle.If record count is greater than 0 the script is executed.The scripts updates the count in the table and again the count is found out and the condition is checked and same... (3 Replies)
Hi Forum
Im using sleep in a while loop goes around 10 times. i feed it a variable with the time i what it to sleep for eg sleep $sleepVal and then print system date and time to screen but sometimes 1 second is added to the time why is this
here my code
sleepVal=5
while
do
... (3 Replies)
Hi All,
i am very new to shall script . i am not that much aware of sleep command ,
i want to terminate the sleep command after certain time.
following is my code.
while
loop
sleep 1800
messag=/status.sql
donethe script will be on sleep untill the messag be comes P. here my requirement... (4 Replies)
Hello,
Need a little help with the script below. I can't get it to sleep :( I'm trying to get this to check if the process is running and if it is, wait 10 secs and check again. Keep doing this until it's not running and then stop checking and send the email.
#!/bin/ksh
mailto=`cat... (2 Replies)
Hi Frnz,
I need to execute sleep command but i dont know the definite time.
Let me put my req:
I am running one shell script and this script creates some lock file in temp dir ...now in my script i want one function to go into sleep mode till this lock file exists..one lock file gone that... (6 Replies)
I need help in script.
I want my one script execute every time at 6:30 am and i have no cron access.
So i am putting sleep command there , Script may took half an hour 35 min , it depend upon queries how much it take time, but that is not issue,
So i want according to stop time of... (15 Replies)
Discussion started by: pallvi_mahajan
15 Replies
LEARN ABOUT REDHAT
setsid
SETSID(2) Linux Programmer's Manual SETSID(2)NAME
setsid - creates a session and sets the process group ID
SYNOPSIS
#include <unistd.h>
pid_t setsid(void);
DESCRIPTION
setsid() creates a new session if the calling process is not a process group leader. The calling process is the leader of the new session,
the process group leader of the new process group, and has no controlling tty. The process group ID and session ID of the calling process
are set to the PID of the calling process. The calling process will be the only process in this new process group and in this new session.
RETURN VALUE
The session ID of the calling process.
ERRORS
On error, -1 will be returned. The only error which can happen is EPERM. It is returned when the process group ID of any process equals
the PID of the calling process. Thus, in particular, setsid fails if the calling process is already a process group leader.
NOTES
A process group leader is a process with process group ID equal to its PID. In order to be sure that setsid will succeed, fork and exit,
and have the child do setsid().
CONFORMING TO
POSIX, SVr4.
SEE ALSO setpgid(2), setpgrp(2)Linux 1.0.0 1994-08-27 SETSID(2)