Linux Learning Notes (2) ~linux directory tree Overview and description

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The Linux directory tree is as follows:

Detailed:
/bin: The system has a lot of directories to place the execution files, but the/bin is quite special. Because the/bin is placed in the single maintenance mode can also be operated instructions. The commands under/bin can be used by root and general account, mainly: Cat, chmod, chown, date, MV, mkdir, CP, Bash and so on.
/boot: This directory is mainly used to set up the boot will use the file, including the Linux core files and boot menu and boot required configuration files and so on. Linux kernel commonly used file name: Vmlinuz, if you are using grub this boot manager, there will also be/boot/grub/this directory.
/dev: On Linux systems, any device and peripherals are present in this directory in the form of files. All you have to do is access a device by accessing one of the files under the directory-/dev/null,/dev/zero,/dev/tty,/dev/lp*, dev/hd*,/dev/sd*, etc.
/etc: The main configuration of the system is placed in this directory, such as the person's account password file, the start of various services and so on. In general, the file attributes in this directory are accessible to the general user, but only root has the power to modify it. FHS does not recommend placing executable files (binary) in this directory. The more important files are:/etc/inittab,/etc/init.d/,/etc/modprobe.conf,/etc/x11/,/etc/fstab,/etc/sysconfig/and so on. In addition, the following important directories are:
/etc/init.d/: The preset startup script for all services is placed here, for example to start or close iptables: "/etc/init.d/iptables start", "/etc/init.d/iptables Stop"
/etc/xinetd.d/: This is the so-called Super Daemon Management of the various service profiles directory.
/ETC/X11/: The various profiles associated with the X Window are here, especially xorg.conf, the X Server profile.
/home This is the system preset user home directory. When you add a general user account, the default user home directory will be standardized here. More importantly, the home directory has two code names OH:
~: Represents the current user's home directory, and
~dmtsai: It represents Dmtsai's home directory!
/lib: The function Library of the system is very much, and the/lib place is the function library that will be used at boot, and the function library that the instruction under/bin or/sbin will call. What is a function library? You can think of him as a "plug-in", some instructions must have these "plug" to be able to successfully complete the implementation of the program meaning. It is particularly important to/lib/modules/this directory because of the?? The directory will place the core-related modules (drivers) Oh!
/media:media is the "media" in English, as the name implies, this/media is placed under the removable device! The devices, including soft discs, CDs, DVDs and so on, are temporarily mounted here. Common file names are:/media/floppy,/media/cdrom, and so on.
/MNT: If you want to temporarily mount some additional devices, it is generally recommended that you place them in this directory. In ancient times, the use of this directory is the same as/media! Just after the/media, this directory is used for temporary loading.
/OPT: This is a directory for third-party software placement. What is a third-party collaboration software? For example, the KDE desktop Management system is a standalone project, but it can be installed on a Linux system, so KDE software is recommended to be placed in this directory. Also, if you want to install additional software on your own (not provided by the original distribution), you will be able to install your software here as well. However, in the previous Linux system, we are still accustomed to place in the/usr/local directory!
/root: The home directory of the system administrator (root). The reason for this is that if you go into single-player maintenance mode and only mount the root directory, that directory will be able to have the root home directory, so we would like Root home directory and root directory in the same partition slot.
/sbin:linux has a lot of instructions for setting up the system environment, which only the root can use to "set up" the system, the other users can only be used to "query" only. Placed under the/sbin for the boot process required, which includes the boot, repair, restore the system required instructions. As for some server software programs, they are generally placed in/usr/sbin/. System binary, which is generated by the natively installed software, is placed in the/usr/local/sbin/. Common directives include: fdisk, fsck, Ifconfig, Init, MKFS, and so on.
/srv:srv can be regarded as the abbreviation of "service", which is the data directory that some services need to use after the network service is started. Common services such as WWW, FTP and so on. For example, the Web page data required by the WWW server can be placed inside the/srv/www/.
/tmp: This is where the general user or an executing program temporarily places the file. This directory is accessible to anyone, so you need to clean it up regularly. Of course, important information cannot be placed in this directory. Because FHS even suggested that when the boot, you should be the/TMP data are deleted.

/lost+found: This directory is a directory that is generated using the standard EXT2/EXT3 file system format, in order to place some missing fragments into this directory when the file system is in error. This directory usually exists at the top level of the splitter slot, for example if you add a hard disk to/disk, which will automatically generate a directory "/disk/lost+found" in this system.
/proc: This directory itself is a "virtual filesystem", the information he placed in memory, such as the system core, travel information (process), the state of peripheral devices and network status, and so on. Because the information in this directory is in the memory, so it does not occupy any hard disk space Ah! More important files such as:/proc/cpuinfo,/PROC/DMA,/proc/interrupts,/proc/ioports,/proc/net/* and so on.
/sys: This directory is actually very similar to/proc, but also a virtual file system, which is also the key to record the information related to the core. Includes the core modules currently loaded and the core detected hardware device information and so on. This directory also does not account for HDD capacity.

/usr/x11r6/: The directory placed for the X Window system important information is named X11R6 because the final x version is the 11th version, and the 6th release of the version is intended.
/usr/bin/: The vast majority of users can use the instructions are placed here! Please note the difference between him and/bin. (whether it is related to the boot process)
/usr/include/: the header (header) of the programming language and the include file (include) place, when we install some materials in the tarball Way (*.tar.gz way), we use many of the files contained in the file.
/usr/lib/: A function library containing application software, a target file (object file), and an executable file or script that is not used by the general user. Some soft experience to provide some?? Special instructions to the server settings, these instructions are not often operated by the system administrator, it will be placed in this directory. It is important to note that if you are using a x86_64 Linux system, there may be/usr/lib64/directories to produce Oh!
/usr/local/: The system administrator installs its own downloaded software (non-distribution preset provider) on the machine, it is recommended to install to this directory, which will be easier to manage. For example, your distribution provides an older software, you want to install newer software but do not want to remove the old version, you can install the new version of the software in the/usr/local/directory, can be different from the original version of the software! You can go to the/usr/local yourself to see, the directory is also has bin, etc, include, Lib ... The Secondary catalogue Oh!
/usr/sbin/: System instructions required for non-system normal operation. The most common is the service instruction (daemon) of some network server software.
/usr/share/: Where the shared files are placed, the data placed in this directory is almost always readable by the hardware architecture, because they are almost all text files! These secondary directories are common in this directory:
/usr/share/man: on-line documentation
/usr/share/doc: Description of software miscellaneous documents
/usr/share/zoneinfo: Time zone files related to time zones
/usr/src/General source code is suggested to be placed here, SRC has the meaning of source. The core source code is recommended to be placed in the/usr/src/linux/directory.

/var/cache/: Some of the temporary archives that will occur during the operation of the application itself;
/var/lib/: In the process of executing the program itself, you need to use the directory where the data files are placed. The respective software should have its own directory under this directory. For example, the MySQL repository is placed in/var/lib/mysql/and the RPM database is placed in/var/lib/rpm!
/var/lock/: Some devices or file resources can only be used by one application at a time, if there are two programs using the device, there may be some wrong situation, it is necessary to lock the device (lock), to ensure that the device will only be used for a single software. For example, the burning machine is burning a disc, you think about it, there will be two people at the same time using a burning machine burning tablets? If two people burn at the same time, whose data is written by the film? So when the first person is burning the machine will be locked, the second person must be unlocked (that is, the previous person ran out) to continue to use.
/var/log/: important To Not! This is the directory where the login file is placed! There are more important files such as/var/log/messages,/var/log/wtmp (record the information of the logged in) and so on.
/var/mail/: The directory where personal e-mail is placed, but this directory is also placed in the/var/spool/mail/directory! Usually the two directories are interlinked files!
/var/run/: After some programs or services are started, their PID will be placed in this directory Oh! As for the meaning of PID, we will refer to it in subsequent chapters.
/var/spool/: This directory usually places some queue data, so-called "queue" is a queue waiting for other programs to use the data! This data is usually deleted after being used. For example, the system receives a new letter that will be placed in the/var/spool/mail/, but the letter will be deleted in principle after the user has received the letter. If the letter is not sent out temporarily, it will be put into the/var/spool/mqueue/, and then deleted after being sent out. If it is a work scheduling profile (crontab), it will be placed in the/var/spool/cron/directory!

Linux Learning Notes (2) ~linux directory tree Overview and description