Shell Programming--shell Common commands

Browser tab switch: Ctrl+tab

Terminal
Open Terminal Quick build: ctrl+alt+t
Close Terminal shortcut key: Ctrl+shift+q
Open a new Terminal tab shortcut: Ctrl+shift+t
Close the Terminal tab shortcut key: Ctrl+shift+w
Switch between terminal pages shortcut key: Ctrl+pgup
Terminate process: Ctrl + C
Exit Program: Ctrl+d
Open Web page in Firefox: Firefox www.baidu.com

Clear screen: Ctrl + L

[Column directory content LS]
Ls-a: List all files and directories
Ls-l: Long Format list
LS-F: Short format list, file name plus a symbol to indicate attributes, executable file plus x, directory/
LS-R: Recursively lists directories and their subdirectories
Ls-t: Sort by file according to modified time
[Create directory MkDir]
Mkdir-p a/b/c: Create parent directory and subdirectories at the same time
[Delete directory RmDir]
Rmdir-p a/b/c: Remove the empty directory when you delete a directory
[Delete file or directory RM]
Rm-r Mydir: Remove the empty directory when you delete the directory. This option must be used when deleting a directory
[Change working directory CD]
CD ~-: Switch to the directory you just left
[Display the file's top K-line content]head-n K Filetest
[Displays the last K line of the file]tail-n K filetest
[Show file contents or merge files Cat]
Cat-n myfile: Displays the contents of the MyFile file and adds line numbers for all rows
Cat file1 file2 > File3: Merge file1,file2 content into File3
Cat > MyFile: Read content from the keyboard and save it to file MyFile, end by Ctrl+d
[String Filter command grep]
Grep-i pattern [file]: The difference between ignoring the case
GREP-V pattern [file]: Reverse search, display mismatched content
[File Sort command Sort]
sort-f [file]: ignoring case
sort-r [file]: Output sort results in reverse order
Sort file1 > File2: Sort file1 in dictionary order and output to File2

[Make the newly modified initialization file effective without rebooting: source file]

[I/O redirection]
<: standard input redirection, usually referred to as input to a file
such as: WC </etc/passwd
Override mode standard output redirect. If the file does not exist, it is created; otherwise overwritten
such as: ls-l >/tmp/dir.out #覆盖方式
>>: Append mode quasi output redirect. If the file does not exist, it is created or appended to its tail.
such as: Ls-l >>/tmp/dir.out #追加方式

[File Rights Management]
Owner Rights U:user, group permissions g:group, external permissions O:other
Basic permissions: Read R:4, write W:2, execute x:1
[Change file Permissions chmod]: Add permissions +, delete permissions-, set permissions =
such as: chmod u+wx,g=rx,o-x testfile
[Change file owner Chown]:chown user filelist
[Change file belongs to group CHGRP]:CHGRP group FileList


[Process Management Basic command]
Ps-f: Viewing a running process
Kill-9 PID: Terminating Process Execution
Pstree: Process tree and Process status query
Top: Dynamic display of running processes
Uptime: Viewing elapsed time and average load of the system
Free: Shows the number of unused and used memory in the system
Vmstat: Reporting on virtual memory usage

[User Management]
System files related to users and groups:/etc/passwd,/etc/shadow,/etc/group
User management: Useradd,usermod,userdel
User group Management: Groupadd,groupmod,groupdel
User Password management: passwd
Example
Create user group: Groupadd groupname
Modify user group: Groupmod-n newgroupname Oldgroupname
Delete user group: Groupdel groupname
Add User: Useradd-d homedir-g groupname-m-S Shell accountname
Set Password: passwd accountname
Modify User: Usermod-l newname oldname
Delete User: Userdel-r AccountName

Shell Programming--shell Common commands