This is backwards. If you do it this way, you will destroy a lock set by another process if you don't get the lock... You only want to set that trap after you acquire the lock.
This User Gave Thanks to Don Cragun For This Post:
Hi,
I have written below check lockfile script but need some tweaking on it.
If there is a lockfile from present, I need the script to retry every 10 seconds to see if the lockfile is still there. After 120 seconds it should send an email.
In my current version, if the script encounters... (6 Replies)
Just tried out the following code from "Using lockfiles in shell scripts":
#!/bin/bash
if ; then
echo "File exists"
else
echo "File does not exists. Create file now."
echo 1 > number.txt
fi
lockfile script.lock
a=$(/usr/bin/tail -n 1 number.txt)
if ; then... (1 Reply)
Hi all,
I have to test some user priviliges. The goal is to be sure that an unauthorized user can't restart some modules (ssh, mysql etc...).
I'm trying to automate it with a shell script but in same cases I got the syslog broadcast message.
Is there any way to simply get a return code... (3 Replies)
Hi,
I am new to this forum, could any one please help me to understand the LOCKFILE command with an example and what exactly it is used for and how it is used.
Thanks
Reshu289 (4 Replies)
Hello,
I have been working on using "flock"/file lock to prevent two instances of a bash script from being executed. Below is a simplified version of what I have to illustrate the flock part. It works as it is set up there below however the piece I am trying to figure out is how to get it to... (2 Replies)
I'm changing my mindset from a few big processes moving data from a few sources under an external, dependency-based scheduler to multiple processes moving data from many sources run by each client cron and possibly interfering with each other. It has the benefits of more granular code but I'm... (11 Replies)
Hi i have a script that check pings and i use flock to so the script wont run
multipul times :
its not the whole script but this is the idea :
(
flock -x -w 3 200 || exit 1
/usr/sbin/fping -c$count -i$interval -a $hosts > $FILE1 2>&1
) 200>/var/lock/.myscript.exclusivelock
now i... (4 Replies)
Discussion started by: batchenr
4 Replies
LEARN ABOUT HPUX
shlock
SHLOCK(1) General Commands Manual SHLOCK(1)NAME
shlock - create lock files for use in shell scripts
SYNOPSIS
shlock -p pid -f name [ -b ] [ -u ] [ -c ]
DESCRIPTION
Shlock tries to create a lock file named name and write the process ID pid into it. If the file already exists, shlock will read the
process ID from the file and test to see if the process is currently running. If the process exists, then the file will not be created.
Shlock exits with a zero status if it was able to create the lock file, or non-zero if the file refers to currently-active process.
OPTIONS -b Process IDs are normally read and written in ASCII. If the ``-b'' flag is used, then they will be written as a binary int. For
compatibility with other systems, the ``-u'' flag is accepted as a synonym for ``-b'' since binary locks are used by many UUCP pack-
ages.
-c If the ``-c'' flag is used, then shlock will not create a lock file, but will instead use the file to see if the lock is held by
another program. If the lock is valid, the program will exit with a non-zero status; if the lock is not valid (i.e., invoking
shlock without the flag would have succeeded), then the program will exit with a zero status.
EXAMPLES
The following example shows how shlock would be used within a shell script:
LOCK=/var/run/innd/LOCK.send
trap 'rm -f ${LOCK} ; exit 1' 1 2 3 15
if shlock -p $$ -f ${LOCK} ; then
# Do appropriate work
else
echo Locked by `cat ${LOCK}`
fi
HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> after a description of HDB UUCP locking given by Peter Honeyman. This is revision 1.9, dated
1996/10/29.
SHLOCK(1)