Linux Permissions and Permissions management

Rights Management

R

W

X

Three types of users

U owner

G-Genus Group

o Other users

Change permissions for three categories of users

Chown Change file owner (only administrators can use this command)

#chown USERNAME File,....

Example #tail/etc/passwd (Find a user)

#ls/tmp-l (look at the files under the user)

#chown [user name]/tmp/abc (change owner)

Demo Step: #cd/tmp (CD to TMP)

#touch ABC (set up file ABC under TMP) the owner of this file is currently root

#ls-L/TMP/ABC (view ABC information)

#tail/etc/passwd (Find a user)

#chown USER2/TMP/ABC (Change the owner of ABC into User2)

#ls-L/TMP/ABC (look at ABC information again)

Chown can also change the directory owner

Demo Step #cd/tmp

#mkdir hi (Create a Hi directory under TMP)

#ls/tmp-l (view tmp information)

#chown User2/tmp/hi (Change the owner of Hi to User2)

#ls/tmp-l (View post-change information) or use #ls-ld/tmp/hi (view directory information, do not add D to see the files under Hi)

Chown-r modifying the owner of a directory and its internal files

Demo Step #cd/tmp/hi (CD to hi directory)

#touch a b c d ABC 123 (Create a file in the Hi directory)

#ls-L/tmp/hi (view information for the created file)

#chown-R User2/tmp/hi (change the owner of the Hi directory and the file under the directory)

#ls-L/tmp/hi (view post-change information)

Chown--reference=/path/to/somefile file,..... (Reference Reference | The owner of the file behind it is the same as the owner of the front file)

Demo Step #cd/tmp

#touch ABC

#chown--REFERENCE=/TMP/ABCD/TMP/ABC (Change the owner of ABC to the same as ABCD)

#ls-L/tmp

Chgrp GRPNAME file, ... Modify file group (same usage as chown) Only administrators have permission to execute this command

Demo Step #groupadd Yourgroup (set up a group, group name Yourgroup)

#cd/tmp

#touch 456 (Create a file under TMP 456)

#chgrp yourgourp/tmp/456 (change 456 genera to Yourgroup)

#ls-L/tmp

Chgrp-r

Demo Step #chgrp-r Yourgroup/tmp/hi (change the group of files in Hi directory and hi to Yourgroup)

#ls-L/tmp (view hi's genus Group)

#ls-L/tmp/hi (view the group of files under the Hi directory)

Chgrp--reference

Chown usename:grpname file, .... (Change both the owner and the group)

Step Demo #chown root:root/tmp/abc (change tmp/abc to master root, group root) = #chown Root.root/tmp/abc

#chown: Root/tmp/abc (change only the genus of ABC does not change the owner) or #chown root:/tmp/abc (change only the genus group)

Chown--reference

chmod: Modify permissions for a file

Modify permissions for three categories of users

chmod MODE file, ...

Chmod-r (Modify the file permissions in the directory)

Chmod--reference=/path/to/somefile file,... (with one file permission as standard, other file permissions modified to be the same)

Demo Step #chmod 750/tmp/abc (convert permissions to 8 binary)

Modify a class of user or some class user rights

U,g,o,a,

chmod user category =mode file, ...

Step Demo #chmod u=rwx/tmp/abc (change the permissions of the ABC owner to RWX)

#chmod u=r,o=r/tmp/abc (Change the permissions of the ABC owner to R, and the other user to R) #chmod UG=R/TMP/ABC (Multiple-class user Modify permissions can be combined write)

#chmod g=rx,o=/tmp/abc (change the permissions of the ABC owner to RX, other users do not have permissions)

Modify a user or some bit permission for a class

User Category U,g,o,a

chmod

Step demo #chmod u-x/tmp/abc (remove the execution authority of the ABC owner)

#chmod u+x,g-x/tmp/abc (adds the execution authority of the ABC owner, removing the execution rights of the group)

#chmod a+x/tmp/abc (Add the execution rights of the ABC three users, and in the case of all three types of users do not have permission to execute) A can be omitted

#chmod u-wx/tmp/abc (remove the WX authority of the ABC owner while operating multiple classes of permissions)

!!!!!!!!!!!!! Practice

1. Create a new user with no home directory OpenStack

2. Copy/etc/skel to/home/openstack

3. The main genus group that changes the/home/openstack and its internal files are OpenStack

4./home/openstack and its internal files, group and other users do not have any access rights

#useradd-M OpenStack (new user OpenStack without home directory)

#finger OpenStack (view user account information)

#ls/home (see House directory, no home directory is correct)

#id OpenStack (view user information)

#cp-R/etc/skel/home/openstack (copy/etc/skel to/home/openstack)

#ls-L/home (view House directory files)

#ls-L/home/openstack/-a (view user hidden file information)

#chown-R openstack.openstack/home/openstack/(the genus group that changes/home/openstack and its internal files are OpenStack)

#ls-ld/home/openstack (view directory information)

#ls-la/hoem/openstack (Product view directory hidden file information)

#chmod-R go=/home/openstack (/home/openstack and its internal files, group and other users do not have any access rights)

#ls-ld/home/openstack

#ls-la/home/openstack

#su-openstack

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Linux Permissions and Permissions management