flock(1) - NetBSD Manual Pages

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FLOCK(1)                NetBSD General Commands Manual                FLOCK(1)


NAME
flock -- Provide locking API for shell scripts
SYNOPSIS
flock [-dnosvx] [-w timeout] file|directory command [args ...] flock [-dnosvx] [-w timeout] file|directory -c command flock [-dnsuvx] [-w timeout] number
DESCRIPTION
The flock utility provides flock(2) access to the command line or scripts. The first two forms lock the specified file or directory while the provided command is executed. If the path does not exist, then a file of that name is created with mode 0600. The third form can use an arbitrary file descriptor number that is pro- vided 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. This is the default.
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. NetBSD 9.99 October 4, 2019 NetBSD 9.99
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