I would appreciate any donations. Wishlist or send e-mail type donations to maekawa AT daemon-systems.org.
FLOCK(1) 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 provided 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. 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 8.0 August 18, 2014 NetBSD 8.0