From: Jookia <contact@jookia.org>
Date: Thu, 23 Jan 2020 04:55:35 +0000 (+0000)
Subject: flock: Add new example using shell IO redirection
X-Git-Tag: v2.36-rc1~259^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=966bcac37a95837011cf3bf5c588509b56994eda;p=thirdparty%2Futil-linux.git

flock: Add new example using shell IO redirection
---

diff --git a/sys-utils/flock.1 b/sys-utils/flock.1
index 0a4da9d468..6762ecb4ce 100644
--- a/sys-utils/flock.1
+++ b/sys-utils/flock.1
@@ -166,6 +166,14 @@ run.  If the env var $FLOCKER is not set to the shell script that is being run,
 then execute flock and grab an exclusive non-blocking lock (using the script
 itself as the lock file) before re-execing itself with the right arguments.  It
 also sets the FLOCKER env var to the right value so it doesn't run again.
+.TP
+.TQ
+exec 4<>/var/lock/mylockfile
+.TQ
+flock -n 4
+This form is convenient for locking a file without spawning a subprocess.
+The shell opens the lock file for reading and writing as file descriptor 4,
+then flock is used to lock the descriptor.
 .SH "EXIT STATUS"
 The command uses
 .B sysexits.h