How to use the which command on Linux system

This article mainly introduces the Linux system which command how to use, the article is very detailed, has a certain reference value, interested friends must read it!

The main function of the Linux system which command is to search for the location of a system command in the path specified by the PATH variable and return the first search result.

Syntax which [file...] Parameter:-n specifies the length of the file name, which must be greater than or equal to the longest file name of all files.

The-p parameter is the same as the-n parameter, but here the path to the file is included.

-w specifies the width of the field on output.

-V displays version information.

Case demonstration: example 1: find files and display command paths

Command:

Which lsmod

Output:

[root@localhost ~] # which pwd / bin/pwd [root@localhost ~] # which adduser / usr/sbin/adduser [root@localhost ~] # description:

Which searches for runnable files according to the directories in the PATH variables configured by the user! Therefore, the commands found in different PATH configurations are of course different!

Example 2: use which to find out which

Command:

Which which

Output:

[root@localhost ~] # which which alias which='alias | / usr/bin/which-- tty-only-- read-alias-- show-dot-- show-tilde' / usr/bin/which [root@localhost ~] # description:

Unexpectedly, there will be two which, one of which is alias, which is the so-called "command alias", which means that typing which will be equal to the following string of commands!

Example 3: find out the command cd

Command:

Which cd

Output:

Description:

The common command of cd can't be found! Why? This is because cd is a built-in command from bash! But which defaults to find the directory specified in PATH, so of course you can't find it!

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