一个测试下载速度的shell脚本

在linux下用shell来测试下载度，代码如下：

#!/bin/bash
#date:20140210
#used for test server download speed
r_host="188.18.28.19"
r_dir="/home/test0208/tmp"
r_file="$r_dir/ddfile2m"
l_dir="/home/yangjuying/tmp"
l_file="$l_dir/ddfile2m"
l_log="$l_dir/182.18.28.19-download.log"
echo "----------$(date +%y%m%d-%h%m%s)----------" >>$l_log
start_t="$(date +%s)"
scp -p22 -o connecttimeout=10 -o gssapiauthentication=no test0208@$r_host:$r_file $l_file >>$l_log 2>&1
rc="$?"
if [ "$rc" -eq 0 ];then
    stop_t="$(date +%s)"
    file_stat="$(stat $l_file)"
    file_ctime="$(echo "$file_stat" | awk -f "[ .]" 'fnr==5{print $2,$3}' | sed 's/[- :]/ /g')"
    file_ct="$(awk -v t="$file_ctime" 'begin{print mktime(t)}')"
    file_size="$(du -sm $l_file | cut -f1)"
    rm "$l_file"
else
    stop_t=""
fi
if [ -n "$stop_t" ];then
    connect_t=$(($file_ct-$start_t))
    transfer_t=$(($stop_t-$file_ct))
    all_t=$(($stop_t-$start_t))
    speed="$(echo "scale=3;$file_size/$transfer_t" | bc)"
    echo "size:${file_size}mb, all_time:$all_t, connect_time:$connect_t, transfer_time:$transfer_t, speed:${speed}mb/s" >>$l_log
else
    echo "scp error!" >>$l_log
fi