System Performance Assistant monitoring tool-Watch

Real-time monitoring commands, watch is a very useful command, can help you to monitor the results of a command in real time, save the manual run over and over again. The two most common options for this command are-D and-N, where-n indicates how many seconds interval is executed "command", and-D indicates where the highlight has changed.

Examples of usage:
1) Execute the WHO command once every second to monitor the status of the server's current user login
watch-d-N 1 ' who '

2) Watch can run multiple commands at the same time, and the commands are separated by semicolons. The following commands monitor disk usage and the status of files in the current directory, including additions, deletions, and updates to file modification dates.
watch-d-N 1 ' df-h; Ls-l '

System Performance Assistant monitoring tool-Watch