A permission assignment is normal
Basic permission map of two files
Three chmod commands
chmod [options] mode filename
Options
-R recursive
model
[ugoa] [+-=] [rwx]
[mode = 421]
Four actual combat
[root@localhost ~]# touch a.av
[root @ localhost ~] # ll a.av
-rw-r - r--. 1 root root 0 Aug 5 08:23 a.av
[root@localhost ~]# chmod u+x a.av
[root @ localhost ~] # ll a.av
-rwxr - r--. 1 root root 0 Aug 5 08:23 a.av
[root@localhost ~]# touch b.av
[root @ localhost ~] # ll b.av
-rw-r - r--. 1 root root 0 Aug 5 08:24 b.av
[root@localhost ~]# chmod g+w,o+w b.av
[root @ localhost ~] # ll b.av
-rw-rw-rw-. 1 root root 0 Aug 5 08:24 b.av
[root@localhost ~]# chmod g-w,o-w b.av
[root @ localhost ~] # ll b.av
-rw-r - r--. 1 root root 0 Aug 5 08:24 b.av
[root@localhost ~]# chmod u=rwx,g=rw b.av
[root @ localhost ~] # ll b.av
-rwxrw-r--. 1 root root 0 Aug 5 08:24 b.av
[root@localhost ~]# chmod a=rw b.av
[root @ localhost ~] # ll b.av
-rw-rw-rw-. 1 root root 0 Aug 5 08:24 b.av
Digital representation of five permissions
Six actual combat
[root@localhost ~]# chmod 755 b.av
[root @ localhost ~] # ll b.av
-rwxr-xr-x. 1 root root 0 Aug 5 08:24 b.av
[root@localhost ~]# chmod 644 b.av
[root @ localhost ~] # ll b.av
-rw-r - r--. 1 root root 0 Aug 5 08:24 b.av