To suid only need to have a understanding on the line, do not blindly set, otherwise it will affect the stable operation of the system
1, the temporary right to allow different groups to view each other do not create files
[[email protected] ~]# chmod u+s/usr/bin/cat Note: Put Cat in/usr/bin/to run
[Email protected] ~]# Ll/usr/bin/cat
-rwsr-xr-x. 1 root root 54080 November 6 2016/usr/bin/cat
[Email protected] ~]#
2, will give the suid temporary right to remove
[Email protected] ~]# chmod u-s/usr/bin/cat
[Email protected] ~]# Ll/usr/bin/cat
-rwxr-xr-x. 1 root root 54080 November 6 2016/usr/bin/cat
[Email protected] ~]#
3, to give a clear example, passwd born with Suid, can make ordinary users themselves can change the password;
[Email protected] ~]$ LL/USR/BIN/PASSWD
-rwsr-xr-x. 1 root root 27832 June 2014/usr/bin/passwd
[Email protected] ~]$
Linux SUID, SGID, sticky rights