1, create user Gentoo, additional group is bin and root, the default shell is/BIN/CSH, the annotated message is "Gentoo distribution"
Useradd-c "Gentoo distribution"-s/bin/csh-g Bin,root Gentoo
2, create the following user, group and group membership, named Admins group, user Natasha, use admins as a subordinate group, user Harry, also use admins as a subordinate group, user Sarah, not interactive login system, and is not a member of admins, Natasha,harry,,sarah passwords are CentOS.
Idea: groupadd Admins
USERADD-G Admins Natasha
Useradd-g Admins Harry
Useradd-s/sbin/nologin Sarah
3. Echo "CentOS" |stdin–stdin Natasha
echo "CentOS" |stdin–stdin Harry
echo "CentOS" |stdin–stdin Sarah
3, copy the/etc/fstab file to/var/tmp, set the file owner to Wangcai read and write permissions, the group has read and write permissions for the SysAdmins group, other people do not have permission
Groupadd sysadmins;usermod-g sysadmins wangcai;cp/etc/fstab/
/var/tmp/chmod 660/var/tmp; Chown-r wangcai:sysadmins/var/tmp/
4, mistakenly deleted the user Wangcai home directory, please rebuild and restore the user home directory and the corresponding permission attributes
Mkdir/home/magetest
Cp-r/etc/skel/. [^.]/home/magetest/
a bit of a head, a file that ends at any character, does not contain. and../
Chown-r Magetest.magetest/home/magetest
Chmod-r 700/home/matgtest
5, the new files created in/testdir/dir automatically belong to the G1 Group, group G2 members such as: Alice can have read and write access to these new files, group G3 members such as: Tom can only have read access to the new file, other users (not belonging to G1,G2,G3) cannot access this folder.
1) mkdir-p Testdir/dir;groupadd g1;chgrp g1/app/testdir/dir;chmod 2750/app/testdir/dir/
2) Create directory SGID create user Alice belongs to G2 Tom belongs to G3
6. Back up ACL permissions for all files in/testdir/dir to/root/acl.txt, clear all ACL permissions in/testdir/dir, and finally restore ACL permissions
Directories containing ACL permissions backup and restore using the packaging tool
Solution Ideas:
1) Backup
TAR-CVF House.tar House
Getfacl-r House > Acl.txt
2) Restore
TAR-XVF house.tar-c/var/tmp
CP acl.txt/var/tmp
Setfacl--restore Acl.txt
Linux users, groups, permissions, combination exercises
