Many people may see on TV or in the movies had a similar scenario, a hacker in the face of a black screen, floating above the dense character, Bang Bang meal knock, steal information to complete the task.
Linux newborn when there is no graphical interface, all operations thanks to the completion of the command, just like on TV as a hacker, full of mysterious and obscure.
In recent years, although Linux developed very rapidly, more and more friendly and graphical interface, but the real development process, Linux command line application still plays a very important seat. You can not say that the command line, it will not Linux.
Linux provides a large number of commands, which can effectively use a lot of work done, such as disk operations, file access, directory operations, process management, file permissions settings. Linux distributions with minimal command also has more than 200 here only the most important and frequently used commands.
Use the command
command [-options] [parameter1] ...
command: command name, the corresponding function English words or abbreviations of words
[-options]: Option can be used to control commands, may be omitted
parameter1 ...: arguments passed to the command, which can be zero or more of a
Example: ls -a / home
How to view the documentation:
1) - help
Linux commands are generally built with the help of information, not all commands it comes with this option.
As we want to see the usage of the command ls: ls --help
2) man (there is a problem to find a man)
man is a Linux manual provided, including most of the commands, functions, instructions for use. The manual is divided into many sections (section), you can specify different sections using man to browse different content.
man in each section have the following meanings:
1, Standard commands (standard commands)
2, System calls (system calls, such as open, write)
3, Library functions (library functions such as printf, fopen)
4, Special devices (device description file, / dev various equipment)
5, File formats (file formats, such as passwd)
6, Games and toys (games and entertainment)
7, Miscellaneous (miscellaneous, conventions and agreements, such as Linux file systems, network protocols, ASCII code; environ global variable)
8, Administrative Commands (administrative commands, such as ifconfig)
For example, we want to see ls Usage: man 1 ls (1: the number "1", it represents a section, standard commands)
In fact, we do not specify the first few chapters also used to view, such as, man ls. However, this case, if the name of the command name and function exactly the same name (eg: printf), it is both the command can also be a function of the library, if we do not specify the chapter number, man printf, only view use command does not query function usage, because man is the chapter number in the order of manual searching.
Therefore, the use of man's Manual best to specify the chapter number:
In the first few letters of a command and win at the same time, press the tab key, the system will automatically help us to complete the command.
When the system execute some commands, press the arrow keys to look at the previous command, history will be executed commands listed.
The content should be displayed on the terminal is saved to the specified file.
Such as: ls> test.txt (test.txt if does not exist, it is created, exists its contents are overwritten)
When we search for files or folders containing a keyword, often you need to use the pipeline, combined with grep (search command) used together.
Pipeline we can understand the real life of the tube, the tube a plug stuff in, take out the other end, where "|" is divided into left and right ends of the left plug something, get something right.
Such as: ls | grep g, ls would have to display the contents of the screen into the left end of the pipe, and then remove these elements from the right side, in the content search there "g" keyword text.
File, disk management:
ls: Display directory contents
-l: List Display
-a: Display (hidden files beginning with ".") All Files
-h: with -l humane way to display the file size
clear: clear the display on the terminal can also use the keyboard shortcut: Ctrl + l ( "l" letter)
cd: Change directory
cd / mnt enter mnt (specify) directory
cd .. parent directory access
cd - can enter a directory entry
cd ~ to enter the user's home directory (~: to refer to the home directory, the home directory refers to / home in the user directory, not pure / home directory)
pwd: Display the current working directory absolute path
Note: If the path is a path starting from the root, the path in front of the need to add "/", such as "/ mnt", usually enter a directory folder, without the first "/."
mkdir: create directory
-p recursively create a folder in a specified path
cat: displays the contents of a text file
rm: Remove files or directories
-r: This parameter must be added when you delete a folder
-f: Force delete files
cp: Copying Files
-r: copies a folder
-i: When there are duplicate files, remind you whether to overwrite
-v: Display copy progress
cp vim_configure / code / -ivr vim_configure copy the folder to the code directory
mv: move files or change the file name
-v: display moving progress
mv file1 file2 file1 renamed file2mv vim_configure / code / vim_configure / moved to the code directory
which: Check the directory where the command
tar: compression and decompression command
gzip format (compressed suffix .tar.gz):
Compression Usage: tar cvzf compression bags name File 1 File 2 ...
c: create, create
v: displays the compression progress
z: Specifies the format is gzip compressed format, file.tar.gz
You can order any of these three parameters, parameters can be added in front of "-", such as: -zcf
f: behind file, document, f must be a compressed file, so when used together these four options, f must be placed at the end, such as: zxvf
Examples: tar zcvf test.tar.gz 1.c 2.c 3.c 4.c to 1.c 2.c 3.c 4.c compressed into zcvf test.tar.gz
The above operation, you could write: tar zcvf other.tar.gz * .c (. * C represent all .c)
Decompressed Usage: tar zxvf compression bag name
x: Representative decompression operation
z: Specifies extracting archive format is gzip format, file.tar.gz
Usage, and create a compressed package uses the same option order is the same.
Examples: tar zxvf new.tar.gz extract out the new.tar.gz
In fact, "z" parameter can be omitted, in which case, no matter what the format archive decompression are:
Unzip to a specified directory: -C (uppercase "C")
Examples: tar -xvf new.tar.gz -C ./test/ will new.tar.gz extract to test under the current directory
bz2 format (compressed suffix .tar.bz2):
When operating in gzip format and the same, the difference between: bz2 format parameter "j" designated
Compression Usage: tar jcvf compression bags name File 1 File 2 ...
Examples: tar jcvf bk.tar.bz2 * .c
Decompressed Usage: tar jxvf compression bag name
Examples: tar jxvf bk.tar.bz2
Unzip to a specified directory: -C
Examples: tar jxvf bk.tar.bz2 -C ./
User rights management:
chmod: change file permissions
There are two ways to use chmod format (letter method and digital method)
chmod u / g / o / a + / - / = rwx file
[U / g / o / a] description
u: user indicates that the owner of the file
g: group represents the owner of the file belonging to the same group (group), that is the user group
o: other that other people outside
a: all this represents all three-is
[+ - =] Instructions
+: Increases authority
-: Revoke privileges
=: Set permissions
r: read-readable representation
w: write expressed writable
x: excute represent executable
chmod o + w file to other users of the file increases file write permissions
chmod u-r file to the file minus the file owner read access
chmod g = x file settings file file with executable permissions for groups of users, while removing the read and write permissions
"Rwx" These rights can also be used instead of numbers
r: read permission numerals "4"
w: Write permission, numerals "2"
x: execute or switch privilege, numerals "1"
-: Does not have any rights, numeric code "0"
Such as the implementation of: chmod u = rwx, g = rx, o = r filename
It is equivalent to: chmod u = 7, g = 5, o = 4 filename
chmod 751 file
Owner of the file: read, write, execute permissions
Same group of users: read, execute permissions
Other users: execute permissions
chmod 777 file
All users have read, write, and execute permissions
Note: If you want to add the same permissions recursively all directories, you need to add the parameter "-R".
Such as: chmod 777 test -R
All files plus 777 recursive test directory.
ps: View system processes
ps -a view all processes of the current user
ps -e view the system all the processes
kill: kill the process process ID is specified, with the use ps
kill 9133 9133 for an application corresponding to the process ID
Some processes can not directly kill, this time we need to add a parameter "-9", "-9" on behalf of a forced end.
ifconfig: View or NIC configuration information
If we just knock: ifconfig, it will display all card information:
Specifies card information: ifconfig eth0 ( "0" to a number)
Set ip: sudo ifconfig eth0 192.168.31.165
sudo is to allow the system administrator to allow ordinary users to perform some or all of the root command a tool to reduce the root user login and management time and improve safety.
ping: to test network connectivity
ping 10.221.0.24 not automatically stop, press "Ctrl + c" to stop
ping 10.221.0.24 -c 4 "-c" representative of the number of packets sent, here 4 times
who: View information on the current system login user
The first column shows Username
The second column shows the terminal name
The third column shows the landing time
If it is a graphical interface to exit the current terminal
If you are using ssh remote login, logout account
shutdown -h now shutdown immediately, which now corresponds to the time of the state 0
shutdown -h 20:25 20:25 system in today's club shutdown
shutdown -h +10 system automatically shut down after ten minutes
reboot: Restart the computer