Common shell commands under Linux

1. Export Env_var=value #修改环境变量

2. Env #查看环境变量值

3. Hostname #显示主机名

4. readlink-f filename #文件的完整路径

5. Tar xzf filename.tar.gz; #解压, followed by the-C dirname, means to extract to a directory.

6. Tar czf filename.tar.gz dirname #压缩

7. Ctr+r use keywords to search for the commands we have used.

8. History #查看历史命令

9. kill-9 PID #kill掉某个进程

. Kill%<jobid> #kill Jobid corresponding process

Ll-rt #列出所有文件, and the reverse sort of the modified time,-R for the reverse,-t to sort by time.

ll is equivalent to ls-l, which displays file information in the form of a log list. Each item contains 9 fields. The following were:

Field 1: Represents a file's properties, and the first letter represents the file type. "-": Normal file, "D": Directory, "-L": symbolic link; After 9 letters for file permissions, rwx (read and write execution)

The file is the owner of the permissions, group user rights, and other user rights.

Field 2: Number of file links and directory subdirectories, the default value is 2 for the directory, because the directory defaults to two subdirectories, respectively, '. ' and '. ', which indicates the current directory and its parent directory

Field 3: Owner of the file;

Field 4: The group where the owner of the file resides;

Field 5: The file size, in bytes. For a directory, the size of the directory itself, excluding the size of its child files.

Field 6,7,8: File creation month, date, time.

Field 9: File name, if it is a symbolic link, there will be a pointer to it.

PS #列出所有活动进程, commonly used PS-EF and PS aux,-e for all programs, E for listing the environment variables used by the program, F indicates the display of a tree structure, indicating

The interrelationship of the program. A represents all programs (except session leaders), and u represents a process that user-oriented format,x shows no control terminal.

PS aux display Results The first item represents the process owner or owner ID, and the second represents the PID

grep xx./-rn #在当前目录下递归查找关键词xx, the line number is typed.

PS aux | grep ABC #含有abc的活动进程, GREP-V ABC does not contain the activity process of ABC. There are several process states:

D Non-interruptible uninterruptible (usually IO)
R is running, or the process in the queue
S is in a dormant state
T stop or be traced
Z Zombie Process

Netstat #显示网络相关信息, commonly used Netstat-nalp. A: Show all options, N: Reject display aliases, can show all numbers converted to digital

L: List only the service status that is in Listen (listening); P: Displays the name of the program that established the related link.

DirName xx #输出一个路径的除文件名之外的其余部分,./xx.txt, Output is.

NC #想要连接到某处: NC [-options] hostname port[s] [ports] ...

Bind port Waiting for connection: Nc-l-P Port [-options] [hostname] [port]

Chat: Host1:nc-lp Port; HOST2:NC hostname port So you can send messages to each other.

File transfer: Host1:nc-lp port > Log.txt; HOST2:NC hostname Port < Log.txt

Port scan: nc-v-z-w2 192.168.0.80 1-140 #-V: verbose output;-Z: Turn off input and output;-w:secs timeout.

Telnet #Internet远程登陆服务的标准协议和主要方式, using telnet hostname port.

Screen # Screen-s XX: Set up a session;c-a D to leave this Session;screen-ls: List screen session; Screen-r XX: Resume session.

Nohup #nohup command to run commands specified by the command parameter and any related ARG parameters, ignoring all hang-up (SIGHUP) signals.

If the output of the Nohup command is not redirected, the output is appended to the Nohup.out file in the current directory.

21. REDIRECT #1: Standard output, 2: Error output, such as sh test.sh > res.out 2>&1, redirect standard error output to standard output, and standard output redirected to Res.out. 1>&-turn off standard output.

Common shell commands under Linux