4.1 file processing command
4.1.1 command processing format and directory command ls
Command Format: Commands - [Options] - Parameters
例：ls -la /etc
Description: 1) the use of individual commands do not follow this format
2) When there are multiple options, you can write together
3) simplify and complete the options -a option -all equal
* Display file directory: ls
Command name: ls
Command English original intent: list
Path where the command: / bin / ls
Execute permissions: All users
Description: display the directory file
Syntax: ls [options] [-ald file or directory
-a show all files, including hidden files (all in all)
-l detailed information display (long length)
-d View Directory attributes ls -ld / etc
-h humane appear in the actual display unit (do not use this command, the default display bytes) (Humanity Human)
-i id file to view the file or folder
*-rw-r–r--
The first representative of the file type: - binary files
d directory file
l soft link file
Back nine into three groups (rwx): first group: u Owner
Second set: g belonging group
The third group: o others
r: read permission w: Write permission x: execute permission
4.1.2 directory processing command
* Create a new directory: mkdir
Command name: mkdir
Command English original intent: make directories
Path where the command: / bin / mkdir
Execute permissions: All users
Syntax: mkdir -p [directory name]
Description: Create a new directory
-p create recursive
Examples: $ mkdir -p / tmp / Japan / boduo (create a directory that does not exist in the directory to add -p)
$ Mkdir / tmp / Japan / longze / tmp / Japan / cangjing (you can create multiple directories under the directory already exists, separated by a space)
* Change directory: cd
Command name: cd
Command English original intent: change directory
Command the path: shell built-in commands
Execute permissions: All users
Syntax: cd [directory]
Description: Change directory
Examples: $ cd / tmp / Japan / boduo (switch to the specified directory)
$ Cd ... (return to parent directory)
* Displays the current directory: pwd
Command name: pwd
Command English original intent: print working directory
Path where the command: / bin / pwd
Execute permissions: All users
Syntax: pwd
Description: Displays the current directory
Examples: $ pwd
* Delete empty directory: rmdir
Command name: rmdir
Command English original intent: remove empty directories
Path where the command: / bin / rmdir
Execute permissions: All users
Syntax: rmdir [directory name]
Function: Delete empty directory
Examples: $ rmdir / tmp / Japan / boduo
* Copy the file or directory: cp
Command name: cp
English intended command: copy
Path where the command: / bin / cp
Execute permissions: All users
Syntax: cp -rp [the original file or directory] [destination directory]
-r copy directories
-p preserve file attributes
Description: Copy the file or directory
Examples: $ cp /etc/yum.conf / tmp / Japan copying files
$ Cp -r / tmp / Japan / cangjin / tmp / Japan / boduo -r copy directories need to add property
$ Cp -r / tmp / Japan / cangjin / tmp / Japan / hahaha123655 copy directories renamed same time
* Cut, rename the file or directory: mv
Command name: mv
Command English original intent: move
Path where the command: / bin / mv
Execute permissions: All users
Syntax: mv [the original file or directory] [destination directory]
Description: Cut, rename the file or directory
Examples: $ mv / tmp / Japan / cangjin / tmp / Japan / boduo shear directory
$mv /tmp/Japan/cangjin /tmp/Japan/nvsheng 改名
* Delete files or directories: rm
Command name: rm
Command English original intent: remove
Path where the command: / bin / rm
Execute permissions: All users
Syntax: rm -rf [file or directory]
`-R delete a directory
-f enforcement
Description: Delete a file or directory
Examples: $ rm -rf / tmp / Japan delete a directory
4.1.3 file processing command
* Create an empty file: touch
Command name: touch
English intended command: touch
Path where the command: / bin / touch
Execute permissions: All users
Syntax: touch [filename]
Description: Create an empty file
Examples: $ touch haha.list create a file
$ Touch "program files" to create a filename with spaces must be enclosed in double quotes
* Display file contents: cat (tac reverse display)
Command name: cat
Command English original intent: cat
Path where the command: / bin / cat
Execute permissions: All users
Syntax: cat [filename]
Description: The file contents
-n Display line numbers
Examples: $ cat / etc / issue display a file
$ Cat -n / etc / issue file with line numbers
* Page display file contents: more
Command name: more
Command English original intent: more
Path where the command: / bin / more
Execute permissions: All users
Syntax: more [filename]
(Spaces) or f page
(Carriage return) line feed
q or Q to exit
Description: page display file contents
Examples: $ more / etc / services display a page long document
* Display file contents page (page up available, searchable): less
Command name: less
Command English original intent: less
Path where the command: / usr / bin / less
Execute permissions: All users
Syntax: less [filename]
(Space) f or Down
Page up Page Up
(Carriage return) downward linefeed
Wrap Up arrow
/ Key words search keywords
n jump to the next search word
q or Q to exit
Description: page display file contents (available page up)
Examples: $ less / etc / services display a page long document
* Display the file in front of a few lines: head
Command name: head
Command English original intent: head
Path where the command: / usr / bin / head
Execute permissions: All users
Syntax: head [filename]
Function Description: Display the previous file lines
-n specified number of lines (the line 10 is displayed is not specified)
Examples: $ head -n 20 / etc / services file is displayed in front of the line 20
* Display last few lines of the file: tail
Command name: tail
Command English original intent: tail
Path where the command: / usr / bin / tail
Execute permissions: All users
Syntax: tail [filename]
Description: The last few lines of the display file
-n specified number of lines (the line 10 is displayed is not specified)
-f dynamic display file contents end
Examples: $ tail -n 20 / etc / services file displays the last 20 lines
$ Tail -f / var / log / messages dynamically display the log file does not automatically exit monitoring interface, you need to press ctrl + c
4.1.4 Link command
* Generate link files: ln
Command name: ln
Command English original intent: link
Path where the command: / bin / ln
Execute permissions: All users
Syntax: ln -s source file [file] [target]
-s Create a soft link (without the s is to generate a hard link)
Description: Create link files
Examples: $ ln -s jin.txt jin.yin generate a hard link
$ Ln jin.txt jin.ruan generate soft link
Hard link is equivalent to copy files, but both files synchronized with each other. Lost the original file is also all right, all the same properties as the original one, identifying nodes through i
Soft links permission is lrwsrwsrws, small file size, file name pointing
