Ln create shortcut keys (called shortcut keys in the window system, soft connection file in Linux )
Syntax: ln –s file name 1 file name 2 (create a new shortcut key can not have the same name), as shown in the figure:
ll view all files
Detailed user management:
authority management:
ll means view all content
File execution permissions
Give root permission, other users do not have permission:
Current environment
The root user created / data / file
root.root
problem:
admin-a Failed when normal user wants to execute / data / file
demand:
Ordinary users want to execute root user files
analysis:
File-no execute permission
User-The root user only has write and read permissions
admin-a is an ordinary user
Program:
1. Let the root user have execute permission first
chmod +x /data/file
2. The other user who closed the file does not have execute permission
chmod ox / data / file
3. Root test
/data/file
4. Change the user permissions of the file
chown -R admin-a.admin-a /data
5. Ordinary user admin-a to test
su - admin-a
data/file
to sum up:
File operation permissions: rwx
File permissions operation mode: +-=
File user permissions: ugo
Command knowledge:
File permission operations:
chmod [user symbol] [operation symbol] [operation authority] file
For example: chmod ox / data / file
File user attribution:
chown -R [owner] [array] directory
例如：chown -R admin-a.admin-a /data
Find：
find path-name 'file name (can have regular symbols)'
Pipe symbol
Command 1 | Command 2
All content after the execution of command 1 is passed to command 2 through the pipe character
grep filtering
grep keyword
Format 1:
Command 1 | grep command 2
Format 2:
grep keyword file name
-v negate
-n When getting content, display line number
