Quickly learn to use file permissions

4 create a file , And give authority 611( Two ways , A kind of guoa, A kind of nnn)

[[email protected] ~]# touch file1
[[email protected] ~]# ls -l file1
-rw-r--r-- 1 root root 0 Jul 21 20:45 file1
[[email protected] ~]# chmod 000 file
[[email protected] ~]# chmod u+r,w g+x o+x file
chmod: invalid mode: ‘u+r,w’
Try 'chmod --help' for more information.
[[email protected] ~]# chmod u+rw g+x o+x file
chmod: cannot access 'g+x': No such file or directory
chmod: cannot access 'o+x': No such file or directory
[[email protected] ~]# chmod u+rw,g+x,o+x file
[[email protected] ~]# ll file
-rw---x--x 1 root root 13 Jul 20 10:59 file

5. Create directory , And give authority 755( Two ways , A kind of guoa, A kind of nnn)

[[email protected] ~]# mkdir file1
mkdir: cannot create directory ‘file1’: File exists
[[email protected] ~]# mkdir file3
[[email protected] ~]# chmod 755 file3
[[email protected] ~]# ls -l file3
total 0
[[email protected] ~]# ls -ld file3
drwxr-xr-x 2 root root 4096 Jul 22 00:02 file3
[[email protected] ~]# 

6. create a file , And modify the owner and group of the file to other users

[[email protected] ~]# ls /home
user1
[[email protected] ~]# chown user:user file
chown: invalid user: ‘user:user’
[[email protected] ~]# chown use1r:user1 file
chown: invalid user: ‘use1r:user1’
[[email protected] ~]# chown user1:user1 file
[[email protected] ~]# ls -l file
-rw---x--x 1 user1 user1 13 Jul 20 10:59 file
[[email protected] ~]# 

7. Set up suid, Set for file suid( Two ways u+s and nnnn) The way

[[email protected] ~]# ls -ld file3
drwxr-xr-x 2 root root 4096 Jul 22 00:02 file3
[[email protected] ~]# ll file
-rw---x--x 1 user1 user1 13 Jul 20 10:59 file
[[email protected] ~]# chmod 4777 file
[[email protected] ~]# ll file
-rwsrwxrwx 1 user1 user1 13 Jul 20 10:59 file

8. Set up sgid, Set for file sgid( Two ways g+s and nnnn) The way

[[email protected] ~]# chmod g+s file
[[email protected] ~]# ll file
-rwsrwsrwx 1 user1 user1 13 Jul 20 10:59 file

9. Set up sbit, Set for directory sbit( Two ways o+t and nnnn) The way

[[email protected] ~]# ll -d file3
drwxr-xr-x 2 root root 4096 Jul 22 00:02 file3
[[email protected] ~]# chmod o+t file3
[[email protected] ~]# chmod 1000 file3
[[email protected] ~]# ll -d file3
d--------T 2 root root 4096 Jul 22 00:02 file3

10. create a file , Query file acl

[[email protected] ~]# getfacl file4
# file: file4
# owner: root
# group: root
user::rw-
group::r--
other::r--

 Set for file acl  The user is testuser1  Permission is  rwx

[[email protected] ~]# setfacl -m u:testuer:rwx file1

 Set for file acl Of mask:  Permission is r-x

[[email protected] ~]# setfacl -m m::rx file