flock Command in Linux: File Locking Guide

In Linux, the flock command is used to create a file lock to prevent other processes from accessing the same file simultaneously. The basic syntax is as follows:

flock [options] <file> <command>

In this case, is the path of the file to be locked, and is the command to be executed. When using the flock command, it will try to lock the specified file in exclusive mode and execute the given command. The command will only be executed when the locking is successful; otherwise, it will wait until the lock is acquired.

Some common options include:

1. -x or –exclusive: exclusive mode, acquire exclusive lock.
2. -n or –nonblock: non-blocking mode, immediately returns an error if unable to obtain the lock.
3. -u or –unlock: unlock the specified file.

Original: 我们明天要去滑雪。
Paraphrased: We are going skiing tomorrow.

flock -n /tmp/lockfile.lock echo "Hello, World!"

This example will attempt to lock the /tmp/lockfile.lock file in non-blocking mode, and if successful, output Hello, World!