watch
watch to monitor the results of a command to run
-N specifies the time interval
-d watch highlights regional variations.
-t watch command is closed at the top of the time interval, command, outputs the current time
Example:
1) highlight changes every second number of network connections
watch -n 1 -d netstat -ant
2) every second to highlight changes in the number of http link
watch -n 1 -d ' pstree |grep http '
3) monitor changes in the current directory scf files
watch -d ' ls -l |grep scf '
Average load 4) of the output system 10 seconds
watch -n 10 'cat /proc/loadavg'