#! /bin/bash
nic=$1
netdev=/proc/net/dev
if [ $# != 1 ] ; then
   echo "Usage : $0 NIC"
   exit 1
fi
if [ -z "$(grep $nic: $netdev)" ];then
   echo "Invalid NIC"
   exit 1
fi
in_orig=$(grep $nic $netdev|sed "s/$nic://"|awk '{ print $1 }')
out_orig=$(grep $nic $netdev|sed "s/$nic://"|awk '{ print $9 }')
while true
do
   sleep 1
   in=$(grep $nic $netdev|sed "s/$nic://"|awk '{ print $1 }')
   out=$(grep $nic $netdev|sed "s/$nic://"|awk '{ print $9 }')
   in_diff=$(echo $in $in_orig|awk  '{printf "%5.2f", ($1-$2)/1024}')
   out_diff=$(echo $out $out_orig|awk  '{printf "%5.2f", ($1-$2)/1024}')
   in_total=$(echo $in|awk  '{printf "%6.2f", $1/1024/1024}')
   out_total=$(echo $out|awk  '{printf "%6.2f", $1/1024/1024}')
   echo "$nic:IN ${in_diff}K OUT ${out_diff}K TOTALIN ${in_total}M TOTALOUT ${out_total}M"
   in_orig=${in}
   out_orig=${out}
done

diff -u nicmonitor.orig nicmonitor
--- nicmonitor.orig   2012-05-02 19:49:26.253538669 +0800
+++ nicmonitor   2012-05-02 21:45:00.306720215 +0800
@@ -16,10 +16,10 @@
    sleep 1
    in=$(grep $nic $netdev|sed "s/$nic://"|awk '{ print $1 }')
    out=$(grep $nic $netdev|sed "s/$nic://"|awk '{ print $9 }')
-   in_diff=$(echo $in $in_orig|awk  '{printf "%5.2f", ($1-$2)/1024}')
-   out_diff=$(echo $out $out_orig|awk  '{printf "%5.2f", ($1-$2)/1024}')
-   in_total=$(echo $in|awk  '{printf "%6.2f", $1/1024/1024}')
-   out_total=$(echo $out|awk  '{printf "%6.2f", $1/1024/1024}')
+   in_diff=$(awk 'BEGIN{printf "%5.2f", '"$[in-in_orig]"'/1024}')
+   out_diff=$(awk 'BEGIN{printf "%5.2f", '"$[out-out_orig]"'/1024}')
+   in_total=$(awk 'BEGIN{printf "%6.2f", '"$in"'/1024/1024}')
+   out_total=$(awk 'BEGIN{printf "%6.2f", '"$out"'/1024/1024}')
    echo "$nic:IN ${in_diff}K OUT ${out_diff}K TOTALIN ${in_total}M TOTALOUT ${out_total}M"
    in_orig=${in}
    out_orig=${out}

diff -u nicmonitor.orig nicmonitor
--- nicmonitor.orig   2012-05-02 21:45:00.306720215 +0800
+++ nicmonitor   2012-05-04 13:24:34.221711182 +0800
@@ -20,7 +20,11 @@
    out_diff=$(awk 'BEGIN{printf "%5.2f", '"$[out-out_orig]"'/1024}')
    in_total=$(awk 'BEGIN{printf "%6.2f", '"$in"'/1024/1024}')
    out_total=$(awk 'BEGIN{printf "%6.2f", '"$out"'/1024/1024}')
-   echo "$nic:IN ${in_diff}K OUT ${out_diff}K TOTALIN ${in_total}M TOTALOUT ${out_total}M"
+#   echo "$nic:IN ${in_diff}K OUT ${out_diff}K TOTALIN ${in_total}M TOTALOUT ${out_total}M"
+   tput sc
+#   echo -n "$nic:IN ";tput setf 4;echo -n ${in_diff}K;tput sgr0;echo -n " OUT ";tput setf 4;echo -n ${out_diff}K;tput sgr0;echo -n " TOTALIN ";tput setf 4;echo -n ${in_total}M;tput sgr0;echo -n " TOTALOUT ";tput setf 4;echo -n ${out_total}M;tput sgr0
+   echo -n "$nic:IN ${in_diff}K OUT ${out_diff}K TOTALIN ${in_total}M TOTALOUT ${out_total}M"   
+   tput rc
    in_orig=${in}
    out_orig=${out}
 done

无高亮刷屏
echo "$nic:IN ${in_diff}K OUT ${out_diff}K TOTALIN ${in_total}M TOTALOUT ${out_total}M"

高亮刷屏
echo -e "$nic:IN \e[1;31m${in_diff}K\e[0m OUT \e[1;31m${out_diff}K\e[0m TOTALIN \e[1;31m${in_total}M\e[0m TOTALOUT \e[1;31m${out_total}M\e[0m"

无高亮单行输出
echo -ne "\e[s$nic:IN ${in_diff}K OUT ${out_diff}K TOTALIN ${in_total}M TOTALOUT ${out_total}M\e[u"

高亮单行输出
echo -ne "\e[s$nic:IN \e[1;31m${in_diff}K\e[0m OUT \e[1;31m${out_diff}K\e[0m TOTALIN \e[1;31m${in_total}M\e[0m TOTALOUT \e[1;31m${out_total}M\e[0m\e[u"