Second, redirect
1, covering
Command> filename (will get the contents of the command file points to cover in the back)
2, additional
Command >> filename (add the command to get the contents of the file pointed back in)
Third, the user
1. Create a user
useradd username
2, set by the user password
passwd username
3, the user switches
su - username
A user password is required to switch to the root from the normal user password is not required, the user switches from the normal to the root user
4, delete users
userdel -r username
If the -r parameter user name and corresponding directory will be deleted
If no -r parameter will remove the user does not delete the corresponding user directory
Fourth, the operating system usage
1, top view cpu usage
2. Memory: free
3, the hard disk: df
4, process: ps
5, System Activity Report: sar
6, kill running processes:
Step 1: Enter the command ps ux view running processes
Step Two: Use kill -9 pid serial number to kill the process
Help V. View command
man command (e.g. man ls, man ifconfig)
Six, LAMP environment
1、L: linux
2, A: Apatche (server)
3, M: Mysql database
4, P: PHP development language