I found a lock file like this
lrwxrwxr-x 1 sskb apollo 16 Oct 22 22:00 lock -> hostname:2747
(pl. note that hostname is a number like 123.4.5.6)
but this was not shown in the file manager eventhough I had selected to show the hidden files.
I could not even read the... (4 Replies)
how can I lock my keyboard while I'm away from the computer without using lock command. What other commands gives me the option to lock keyboard device?
thanks (7 Replies)
Hi,
We have a lock file being created called lck8c0001 created in Unixware 2.1.2. This is locking a printer.
According to some websites, 8c0001 relates to the device name.
How does one link 8c0001 to those devices listed in the /dev folder?
I have done a ps -lp for all printers and have... (4 Replies)
I need a script that will check for the existence of new files that FTP'd in the morning, results go to log file. The 2nd step is to compare the new file with the previous days file. If the new file size is 30% or more smaller in size then previous day this needs to also be sent to log.
This... (1 Reply)
We have data files that are ftp'd every morning to a SUN server. The file names are exactly the same except for that each has the date included in its name. I have to write script to do 2 things:
STEP 1) Verify that the file arrived in morning.
STEP 2) Compare the file size of the current... (3 Replies)
I have an Essbase installation on Solaris 10 and need to get the backups configured. Unfortunately several key files are locked and Essbase (OLAP application) is not releasing the locks when the Essbase or the applications within stop running. It appears I can use chmod to unlock the files but I... (0 Replies)
Hello all,
If anyone has time, I have a few questions:
How do I do the following in Linux. We are using Red Hat and Oracle Enterprise Linux, which is based on Red Hat too.
1. How to lock the account after a few (like 3) invalid password attempts?
2. How do you lock a screen after 30... (1 Reply)
I am very new to Linux and learning to script. This is for one of my servers at work that I have to keep track off as far as disk space and how it is used. I have tried to go line by line but little things keep chewing me up. I would appreciate any and all help or advice, and Mutt is installed on... (3 Replies)
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,
Below are the 2 files in directory /tmp:
masterCSF242323.img
indexCSF242323.img
1) I want to compare if both the number (242323) are same in both the files. If they are same print - Files matching, else print files do not match.
2) Also if only index file is present in that... (7 Replies)
Discussion started by: apatil65
7 Replies
LEARN ABOUT NETBSD
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