First, check the version information server system
CAT / etc / OS- Release CAT / etc / redhat- Release uname -a # View kernel version information
Second, the user management
# useradd username Add user passwd change password username # passwd # modify the currently logged in user's password
userdel username # Delete user
userdel -f # delete a user name and user home directories # only root can change the password of the specified user name, and does not require check, other users can only enter passwd directly modify their own passwords and the length must be greater than 8 su - username # switch user, - means completely switched, including environment variables whoami # I see which user
/ etc / passwd # store user information files / etc / Group # store user group information file / etc / shadow # password information stored files
Three, sudo command
Execute commands as another user
Before use needs to be configured in / etc / sudoers file
After other users can, via sudo + Command to run with root privileges.