holiday11

holiday11--linux basis

From today I will write my note in English ,hope I will stick to it.

user and authority

• User is an important part in linux system working,user managerment include user and group managerment.
• In linux,no matter log in the system locally or remotely,every system must have a account ,and have different usage rights in different system resource
• In linux ,you can appoint every user hava different competence for different file or diectory
• file/directory competance include:

word	abbreviation	number
read	r	4
write	w	2
execute	x	1

• In real development ,we can pre-set permissions for a grup ,then add different user into the group ,thereby no need to set permissions for every user.

ls -l expend

• ls -l can view files detalis in directory,followed by left to right is:
  • competance, first char is d mean directory
  • number of hard links, popular speaking,that mean how many way to access current directories and files
  • owner, the owner of files or directories in the home directory is usually the current user
  • group
  • size
  • time
  • name

chmod simple to use

• chmod could modify user/group permissions on files/directories
• command format followed:

chmod +/-rwx file/directory

means of rwx

• file:
  • r:can use cat to view the file
  • w:can modify the file
  • x:can execute
• directory:
  • r:can use ls to view the directory
  • w:can add or modify or delete file in the directory
  • x:can use cd to enter the directory

holiday11--English grammar

be format and useage

be format:

be is am are was were being been

1. The man is back.
2. They are back.
3. He was back.
4. They were back.
5. They have been back.