Linux 获取时间差精确到ms

#! /bin/bash 
#filename: test.sh 
# arg1=start, arg2=end, format: %s.%N 
function getTiming() { 
    start=$1 
    end=$2 
    
    start_s=$(echo $start | cut -d '.' -f 1) 
    start_ns=$(echo $start | cut -d '.' -f 2) 
    end_s=$(echo $end | cut -d '.' -f 1) 
    end_ns=$(echo $end | cut -d '.' -f 2) 
 
 
# for debug.. 
#    echo $start 
#    echo $end 
 
 
    time=$(( ( 10#$end_s - 10#$start_s ) * 1000 + ( 10#$end_ns / 1000000 - 10#$start_ns / 1000000 ) )) 
 
 
    echo "$time ms" 
} 
 
 
 
 
echo "This is only a test to get a ms level time duration..." 
start=$(date +%s.%N) 
ls >& /dev/null    # hey, be quite, do not output to console.... 
end=$(date +%s.%N) 
 
 
timediff=`getTiming $start $end`
echo "时间差：${timediff}"