linux file and directory

1 how to close your computer?

step 1:sync

step 2:shutdown -h

step 3:reboot

step 4:halt(=showdown -h now +power off)

2 attribute of file

10 bits

1:type of file

2~4:user

5~7:group

8~10:others

3 chage group

eg:chagrp [group name][file name]

4 add a user's group

eg:groupadd

5 change user

chown[-R] counter file name/group name file name

where -R means all subfiles of current file

6 change authority of user's reading,writing and executing

eg:chmod[-R] xyz(means figure) file name

where the meaning of -R is as same as chown's

eg:chown u=rwx,og=rx test/test2

when add/minus some authorities,you can see that

eg:chown a-x test/test2

where u for user,o for others, g for group,a for all

7 umask value

eg:umask xxx

if you want to estabish a document,xxx's maximum is 777,

else common file 666

8 change special attribute of file

eg:chattr [+-=][ASaci][file or document name]

9 list special attributes of a file/document

eg:Isattr [-aR][file/document]

10 how to search a file

eg:which test

where test is a file

eg:whereis [-bmsu][file name]

eg:locate

if your system has not this command, you can download

packet mlocate by using command "yum install -y mlocate"

eg:find [path][para]

11 linux file types

eg: - for regular file

d for directory

l for link

b for block

c for seris device

s for socket

12 how to estabish hard links or symbolic links

eg:ln[-s][source file][dst file]