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shlock(1) [bsd man page]

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)

Check Out this Related Man Page

SHLOCK(1)						    InterNetNews Documentation							 SHLOCK(1)

NAME
shlock - Create lock files for use in shell scripts SYNOPSIS
shlock [-b|-c|-u] -f name -p pid 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 whether the process is currently running. If the process exists, then the file will not be created. shlock exits with a zero status if it could create the lock file, or non-zero if the file refers to a 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. -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. -f name name is the name of the lock file shlock attempts to create. If the file already exists, it will read the process ID from the file and exit with a non-zero status if this process is currently active. -p pid pid is the process ID to write into the file name. -u For compatibility with other systems, the -u flag is accepted as a synonym for -b since binary locks are used by many UUCP packages. EXAMPLES
The following example shows how shlock would be used within a shell script: LOCK=<pathrun in inn.conf>/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> for InterNetNews after a description of HDB UUCP locking given by Peter Honeyman, and improved by Berend Reitsma to solve a race condition. Converted to POD by Julien Elie. $Id: shlock.pod 8357 2009-02-27 17:56:00Z iulius $ INN 2.5.2 2009-05-21 SHLOCK(1)

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