What is Dev-Null ?

/dev/null is a special file in Unix-like systems known as the "null device." It is often used to discard unwanted output, effectively acting as a "black hole" for data. When you redirect output to /dev/null, it simply throws it away without any effect. This is especially useful when you want to suppress error messages (stderr) or prevent unnecessary output from being displayed on the screen.

For example, in the command:

$ find / -type f -perm -4000 2>/dev/null

• find / searches the entire file system for files.

• -type f limits the search to files (not directories).

• -perm -4000 looks for files with the SUID (Set User ID) permission, which is often used for programs that require elevated privileges to execute.

• 2>/dev/null redirects the standard error output (stderr, represented by 2) to /dev/null, which suppresses any error messages (e.g., permission denied errors when the find command tries to access directories that the user doesn't have permission to).

This technique is commonly used when you want to perform an action without cluttering the output with error messages, allowing the system to focus on the results of your search or command.