WHO> AAA &
Run the WHO command in the background, and enter the AAA
SAR -A View CPU usage
SAR -D View Disk Run Status
TOP application overcomes system resources
Iostat View System I / O
Run multiple background programs:
(cmd1, cmd2, cmd3) &
Switch program works in front / background
BG%
FG%
% Is the job number
Kill -9 forced to kill the process
Kill -l Look at the list of termination signals
When a background command has added nohup, the parent process is exited, and the No. 1 process init will take over the background process.
Nice -n command
The larger the N value, the more priority, and the system priority value is between [1,39] after the addition and subtitude.
PS display information information (often cooperate with grep to use, if you want to check an application):
-e Shows all users' information
-f display details
-l display process priority
Shell_Program Arg1 Arg2 ....
$ 0 $ 1 $ 2
If you want to use more than 9 numbers after $ 9, you must use the curly brackets after $ $, such as $ {10}, $ {24}
$ # Variable: number of parameters-1
$ * Variable: parameter list, not included $ 0
Display environment variables are available:
echo
ENV
set
UNSET deletes the value of a current environment variable
Method for incorporating data into the shell program
EXPORT environment variable
Command line parameters
User input
Read, the parameter is entered by the user when the shell program is running. If the variable specified in the read command exceeds the user input
The quantity, more variables set into null, excess data will be placed to the last variable
