If file not exist create a new one Post: 302199938

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LEARN ABOUT NETBSD

flock

FLOCK(1)						    BSD General Commands Manual 						  FLOCK(1)

NAME

     flock -- Provide locking API for shell scripts

SYNOPSIS

     flock [-dnosvx] [-w timeout] lockfile|lockdir [-c command] | [command ...]
     flock [-dnsuvx] [-w timeout] lockfd

DESCRIPTION

     The flock utility provides flock(2) access to the command line or scripts.  The first form locks a file or directory while the command pro-
     vided is executed.  If the file or directory does not exist, then a file is created.

     The second form can use an arbitrary file descriptor that is provided from a shell script for example:

     (
	     flock -s 100
	     # commands to be executed under the lock
     ) 100> /path/to/lockfile

     The following options are available:

     -c command 	Pass a command to a the shell.

     -d, --debug	Provide debugging output.

     -n, --nb, --nonblock
			Don't block and fail immediately if the lock could not be obtained.

     -o, --close	Close the file before executing the command.  This is useful if the child forks and should not be holding the lock.

     -s, --shared	Obtain a shared lock.

     -u, --unlock	Unlock an existing lock.  This is available only for a file descriptor.

     -v, --verbose	On error print an explanation of the failure.

     -w, --wait, --timeout seconds
			Fail if the lock could not be obtained after seconds.

     -x, --exclusive	Obtain an exclusive lock.

EXIT STATUS

     The flock utility exits 0 on success, and >0 if an error occurs.

SEE ALSO

     shlock(1), flock(2)

HISTORY

     An flock utility appeared in NetBSD 6.1.

BSD
								 November 2, 2012							       BSD

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

how to check if the file exist or not?

Discussion started by: gusla

2. Shell Programming and Scripting

Have a shell script check for a file to exist before processing another file

Discussion started by: heprox

3. Shell Programming and Scripting

To check whether a directory is exist and if it is not, create it

Discussion started by: sabya

4. Shell Programming and Scripting

How to Check whether list file present in TXT file exist or not

Discussion started by: supriyabv