How do you lock a file in Linux?

Locking files with flock. One common way to lock a file on a Linux system is flock . The flock command can be used from the command line or within a shell script to obtain a lock on a file and will create the lock file if it doesn’t already exist, assuming the user has the appropriate permissions.

How does file locking work?

File locking is a mechanism that restricts access to a computer file, or to a region of a file, by allowing only one user or process to modify or delete it in a specific time and to prevent reading of the file while it’s being modified or deleted.

How do you find what process is locking a file in Linux?

The fuser Unix command will give you the PIDs of the processes accessing a file. dF. fuser will show you which processes are accessing a file or directory. lslocks lists information about all the currently held file locks in a Linux system.

What does it mean to lock a file in Linux?

File locking is a mutual-exclusion mechanism to ensure a file can be read/written by multiple processes in a safe way. In this tutorial, we’ll understand the interceding update problem in a multiple-processes system. Then, we’re going to introduce two types of locks in Linux.

How to lock a file in C program?

And our C code to lock that file: (The code will lock the file, and keep it locked for a while, you can try another terminal to read it, the read will be delayed until lock is released)

Which is an example of mandatory locking in Linux?

In the above example, ls command will write its output to advisory.txt file. Even though we acquire a write lock, still some other process ( Non Cooperating ) can write into the file. This is termed as “Advisory” locking. Test Mandatory Locking: Once again execute the sample program with ‘mandatory.txt’ as the argument.

Which is an example of a file lock?

This macro is used to specify that the region is unlocked. As an example of a situation where file locking is useful, consider a program that can be run simultaneously by several different users, that logs status information to a common file. One example of such a program might be a game that uses a file to keep track of high scores.