Mylinux Note---3rd day

First, LS: Displays the contents of the current file and directory

Format: LS-[option] [directory name]

-A show all hidden files

-L (long format) display file details

-I display index node information for each file

-T sorted by time

-G displays all content except group information in the directory

-L Export the symbolic link file as a normal file

-d lists the directory itself instead of the files in the directory when the directory is encountered

-C mate-lt: Sorts and displays ctime based on CTime (the last time the file state was changed)
Mate-L: Show CTime but sort by name

Second, the default directory structure of Linux

/File system root directory (/), with multiple subdirectories under the root directory

[[email protected]/]# Lsbin Dev etc lib media opt root selinux sys usrboot DVD home Lost+found mnt Proc Sbin SRV tmp var[[email protected]/]#

/boot directories that store the Linux kernel and boot add-ons. The kernel is a vmlinuz-* file

/etc The directory where the operating system environment settings files are stored, mostly text files

/ETC/PASSWD: Files that hold individual user information

/etc/shadow: Save files Saved by user encryption

/etc/fstab: Save files for device tables that need to be mounted automatically when the system starts

/etc/hosts: Save the network host name and IP address of the file

/ETC/RC.D/INIT.D or/ETC/INIT.D: A directory to save the various system service scripts that are required at startup

/etc/resolv.conf: Save the file of the designated name server when the system is logged on externally

/ETC/SYSCONFIG/I18N: Save set language set at startup (lang= "ZH_CN. UTF-8 ") variable

/etc/sysconfig/iptables-config: Save files for Linux firewall iptables environment settings

/etc/sysconfig/network: A file that determines whether to support the network and set the managed name at startup

/etc/sysconfig/network-scripts/ifcfg-eth0: The first Ethernet information file to be used when you start a save

/bin,/usr/bin Save executable program Directory

/bin directory to store default executable program

The/usr/bin directory holds the executable program that the user wants to use

/sbin,/usr/sbin Storage System administrator-specific programs, most of which only super users can execute

/lib Storing shared library files

/var store various log files that detect system changes during execution

/home personal directory with different user master directories

/root Store Superuser's home directory

/dev Store device files for Linux systems

/media,/mnt This directory is a mount point and is a directory that mounts a variety of physical storage devices, which are attached to the process for use.

/srv data required for the service process

/OPT is a directory for some large software or some special software
/tmp directory where temporary files are stored
/usr stores a variety of files supporting user applications, similar to the Win Programs Files folder
/proc Virtual File system

For example: Bring up the CPU, memory information

[[email protected] ~]# cat/proc/cpuinfo <== call up CPU information [[email protected] ~]# Cat/proc/meminfo <== recall Memory information

Expand your knowledge

Pstree: Tree-shaped process

[[Email protected] ~]# pstreeinit─┬─auditd───{auditd}     ├─crond      ├─dbus-daemon     ├─dnsmasq      ├─hald─┬─hald-runner─┬─hald-addon-acpi     │       │             └─hald-addon-inpu      │      └─{hald}      ├─libvirtd───10*[{libvirtd}]     ├─master─┬─pickup     │         └─qmgr     ├─6*[mingetty]      ├─rpc.statd     ├─rpcbind      ├─rsyslogd───3*[{rsyslogd}]     ├─sshd───sshd───bash───bash───pstree      └─udevd───2*[udevd][[email protected] ~]# 

Tree: Table of Contents

Option:-C to differentiate file types by color

-L View the depth of the directory

[[email protected] ~]# tree -cl 2 /boot/boot├──  config-2.6.32-504.8.1.el6.i686├── config-2.6.32-504.el6.i686├── efi│   └──  efi├── grub│   ├── device.map│   ├── e2fs_stage1_5│    ├── fat_stage1_5│   ├── ffs_stage1_5│   ├── grub.conf│    ├── iso9660_stage1_5│   ├── jfs_stage1_5│   ├──  menu.lst -> ./grub.conf│   ├── minix_stage1_5│   ├──  reiserfs_stage1_5│   ├── splash.xpm.gz│   ├── stage1│    ├── stage2│   ├── ufs2_stage1_5│   ├── vstafs_stage1_ 5│   └── xfs_stage1_5├── initramfs-2.6.32-504.8.1.el6.i686.img├──  Initramfs-2.6.32-504.el6.i686.img├── lost+found├── symvers-2.6.32-504.8.1.el6.i686.gz├── symvers-2.6.32-504.el6.i686.gz├── system.map-2.6.32-504.8.1.el6.i686├──  system.map-2.6.32-504.el6.i686├── vmlinuz-2.6.32-504.8.1.el6.i686└── vmlinuz-2.6.32-504.el6.i6864  directories, 26 files[[email protected] ~]#

Third, CD: Switch working directory

Format: CD [directory path name]

The directory pathname is written in two ways: the absolute path, the path from the root (/) to the directory to be toggled, and the relative path, whichever is the current working directory, relative to the current directory path name

① Absolute Path

[[email protected] ~]# cd/etc/sysconfig/<== start with the first level of writing [[email protected] sysconfig]#

② relative path

[[Email protected] etc]# CD sysconfig/<== current directory is the first level in the path, then write the path [[email protected] sysconfig]#

③ returns the last directory in which it was located

Command: CD-

[[email protected] sysconfig]# pwd <== View the full path of the current directory/etc/sysconfig[[email protected] sysconfig]# cd/tmp <== Enter Another directory under directory [[email protected] tmp]# Pwd/tmp[[email protected] tmp]# CD-<== return to the previous directory/etc/sysconfig[[email protected ] sysconfig]# pwd <== return success/etc/sysconfig[[email protected] sysconfig]#

④ Return home Directory

Cd

[[Email protected] sysconfig]# CD [[email protected] ~]# Pwd/root[[email protected] ~]#

Or

cd~

[[Email protected] sysconfig]# CD ~[[email protected] ~]# Pwd/root[[email protected] ~]#

⑤ return to the top level directory

Cd..

[Email protected] sysconfig]# pwd/etc/sysconfig [[email protected] sysconfig]# CD. [Email protected] etc]# Pwd/etc[[email protected] etc]#

Alias is a user-defined form of instruction abbreviation

Usage of aliases

①alias View all aliases set in the current shell, that is, the alias directory

[Email protected] ~]# aliasalias cp= ' cp-i ' Alias l.= ' ls-d. *--color=auto ' Alias ll= ' Ls-l--color=auto ' Alias ls= ' ls--co Lor=auto ' Alias mv= ' mv-i ' Alias rm= ' rm-i ' Alias Which= ' Alias | /usr/bin/which--tty-only--read-alias--show-dot--show-tilde ' [[email protected] ~]#

② Creating aliases

Alia [alias name]=[command to execute]

[[email protected] ~]# alias C=cd[[email protected] ~]# C/[[email protected]/]# lsaaa bin boot Cgroup Dev etc home Lib Lost+found mbr media mnt opt proc root sbin selinux SRV sys tmp usr var[[email protected]/]#

③ Deleting aliases

Unalias [aliases]

[[email protected] ~]# unalias c[[email protected] ~]# C/-bash:c: Command not found[[email protected] ~]#

The ④ child shell does not inherit the alias set in the parent shell command line, and when a new shell is opened, the alias is reset, so it needs to be permanently set up by:

[[email protected] ~]# vim. BASHRC <== Edit. bashrc file, add alias to set

For example: Add alias c=cd that you just set, exit save

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Four. Use of the environment variable path

Path is used to retrieve the command's retrieval path.
①echo $PATH can view the value of the system's environment variable path and use the which command to see the absolute path of a command

[Email protected] ~]# echo $PATH/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin[[email Protected] ~]#

②path= $PATH:/tmp so that we can use the executable file/tmp/as a command

[Email protected] ~]# path= $PATH:/tmp

③ let path take effect permanently, need to add it to/etc/profile or. Bash_profile, reboot takes effect, or Run command directly: Source/etc/profile

Five. Shortcut keys
CTRL + C Cancel command
CTRL + Z Pause command
CTRL + a cursor to the beginning
Ctrl+e cursor to end of line
Ctrl+u Delete all characters before the cursor
Ctrl+k Delete all characters after cursor
Ctrl+l Clear Screen
Ctrl+d Sign Out = = Exit
Ctrl+s lock Command terminal, press any key will not react
CTRL+Q unlock Command terminal

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Mylinux Note---3rd day