RHCAS6

Manage file basic permissions

File permissions
r read
w Write
x perform

The directory permissions
r read
w create a file , Delete file
x perform （cd）

first rwx Indicates the authority of the owner （user）
the second rwx Indicates the permissions of the group to which it belongs （group）
Third rwx Indicates the permissions of others （other）

chmod Modify the permissions
chmod u/g/o/a+/-=rwx filie/dir
You can add or subtract permissions of different owners at the same time

Three digits indicate authority
rwx 111=7
·— 000=0
example ：chmod 777 aaa

chown Modify the person or group of the file
chown user file/dir
chown user:group file/dir
chown :group file
chgrp group file

Manage default permissions and special permissions

suid 4
sgid 1

Default permissions
root And the default permissions for ordinary users to create files

umask
root Of umask yes 0022

umask 022 Modify the authority to 022