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This article shows you how to understand the usr directory in the Linux system, which is concise and easy to understand, which will definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

In the linux file structure, there is a magical directory-/ usr. I haven't paid much attention to it before. Anyway, the program is installed in it, and there is nothing worth tracing back to its origin. Until one day fedora wanted to simplify the entire file system, I saw the discussion and thought, what is the acronym for usr, and where did it come from? During the discussion, most of the views are as follows:

1.usr is the abbreviation of unix system resources.

2.usr is the abbreviation of user.

3.usr is the abbreviation of unix software resources.

According to common sense, it is unlikely to be a user acronym because it conflicts with / home. But it's hard to say whether it's the abbreviation of system resources or software resources. I have checked a lot of things here, only to find that even wikipedia is ambiguous. / usr is the core of the linux system and contains all the shared files.

It is one of the most important directories in the unix system, covering binaries, various documents, various header files, x, and various library files, as well as many programs, such as ftp,telnet and so on.

What used to be / usr was the user's home directory with various user files-now it has been replaced by / home (for example, / usr/someone has been changed to / home/someone).

Modern / usr only stores all kinds of programs and data, and the user directory has been transferred. Although the name of / usr has not changed, its meaning has changed from "user directory" to "unix system resources" directory. It is worth noting that on some unix systems, / usr/someone is still used as a user's home directory, such as Minix.

The / usr file system is often large because all programs are installed here. All files in / usr usually come from Linux distribution; locally installed programs and other things under / usr/local. This may not have to reinstall all programs when upgrading a new version of the system or a new distribution.

Since the files in / usr are not computer-specific and will not be modified in normal use, this directory (file system) can be shared over the network, so that when the administrator installs the new software, all computers that share the file system can use the new software.

At this point, the truth came out. It looks like the / var/run moved to / run a while ago.

I really don't know. I was shocked when I looked at it. It turns out that linux has evolved several times, and the birth and use of many directories have undergone fundamental changes.

/ usr directory structure

/ usr/bin: all executables, such as gcc,firefox, etc. (not included in / sbin and / bin)

/ usr/include: you need to use various header files, compiling files, etc.

/ usr/include/'package-name': program-specific header file

/ usr/lib: so the library files required for executable files

/ usr/local: software that is installed manually is mainly stored here, that is, software that is not installed through Synaptic or apt-get. It has a similar directory structure to the / usr directory. I think it's a good idea to let the package manager manage the / usr directory and put the custom scripts (scripts) under the / usr/local directory.

/ usr/X11R6: X system binaries, library files, documents, fonts, etc. It is not equivalent to the role of / usr, only x can call these library files, etc., other programs do not read or use. Because linux has no native graphical interface, and linux is mostly for server, the graphical interface is meaningless; X11R6 stands for version 11 release 6

/ usr/X11R6/bin: the binary file of x, which contains the necessary files to run x

/ usr/X11R6/include: X related header file

/ usr/X11R6/lib: X library file

/ usr/X11R6/lib/modules: X module, loaded at startup. Lack of video4linux, DRI and GLX and I / O device modules will not work properly

/ usr/X11R6/lib/X11/fonts: font file for x font server

/ usr/doc: documentation. It is actually a soft link of / usr/share/doc

/ usr/etc: a rarely used location for configuration files

/ usr/games: used to include files such as games, but now it is rarely used.

/ usr/info: system-related information, which is a soft link to / usr/share/info

/ usr/man: man manual, moved to / usr/share/man

/ usr/sbin: similar to / sbin,root can be executed. But this directory is not included in the environment variable $PATH. It contains programs similar to chroot, useradd, and in.tftpd and pppconfig.

/ usr/share: it contains shared files between various programs, such as fonts, icons, documents, etc. (the directory corresponding to / usr/local is / usr/loca/share)

/ usr/share/doc: man manual for similar applications. It contains program description files, default configuration files, etc.

/ usr/share/info: not commonly used, has been replaced by man

/ usr/share/man: manual of app

/ usr/share/icons: icons and other files of the application, divided into png,svg and other formats

/ usr/share/fonts: font file, available system-wide, ~ / .fonts is only available to current users

/ usr/src: linux kernel source code and documentation, etc.

/ usr/src/linux: linux source code

/ usr/src/linux/.config: a file produced during kernel compilation; usually produced by the execution of commands' make config', 'make menuconfig', or' make xconfig'

/ usr/src/linux/.depend, / usr/src/linux/.hdepend: 'make dep' detects the files needed for compilation dependencies, which are generated by / usr/src/linux/.config

/ usr/src/linux/COPYING: GNU license

/ usr/src/linux/Makefile: the Makefile required to compile the kernel

/ usr/src/linux/Rules.make: when there is more than one Makefile, execute make according to its rules

/ usr/tmp: a temporary folder that has been abandoned by many distributions.

The above content is how to understand the usr directory in the Linux system. Have you learned the knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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