shell统计/proc/stat实时获取系统cpu使用率

#!/bin/bash
# by Paul Colby (http://colby.id.au), no rights reserved ;)

PREV_TOTAL=0
PREV_IDLE=0

while true; do
 CPU=(`cat /proc/stat | grep '^cpu '`) # Get the total CPU statistics.

#echo "${CPU[0]}";
# echo "${CPU[1]}";
# echo "${CPU[2]}";
# echo "${CPU[3]}";
# echo "${CPU[4]}";

 unset CPU[0]             # Discard the "cpu" prefix.
 IDLE=${CPU[4]}            # Get the idle CPU time.

 # Calculate the total CPU time.
 TOTAL=0
 for VALUE in "${CPU[@]}"; do
  let "TOTAL=$TOTAL+$VALUE"
 done

# echo $TOTAL;

 # Calculate the CPU usage since we last checked.
 let "DIFF_IDLE=$IDLE-$PREV_IDLE"
 let "DIFF_TOTAL=$TOTAL-$PREV_TOTAL"
 #获取不带小数的百分比
 #let "DIFF_USAGE=(1000*($DIFF_TOTAL-$DIFF_IDLE)/$DIFF_TOTAL+5)/10"
 #echo -en "\rCPU: $DIFF_USAGE% \b\b"

 #获取带小数的百分比
 let "DIFF_USAGE=1000*($DIFF_TOTAL-$DIFF_IDLE)/$DIFF_TOTAL"
 let "DIFF_USAGE_UNITS=$DIFF_USAGE/10"
 let "DIFF_USAGE_DECIMAL=$DIFF_USAGE"
 echo -en "\rCPU: $DIFF_USAGE_UNITS.$DIFF_USAGE_DECIMAL%  \b\b\b\b"

 # Remember the total and idle CPU times for the next check.
 PREV_TOTAL="$TOTAL"
 PREV_IDLE="$IDLE"

 # Wait before checking again.
sleep 1
done

使用方法：/bin/bash cpu_usage.sh

CPU: 7.3%

注意：以上脚本只能手动结束运行