我是向东，回忆未来是我的艺名

<?php
$a = array(
    'a' => 'a',
    'b' => 'b'
);
$b = array(
    'a' => 'a',
    'b' => 'b'
);
$a['b'] = null;
unset($b['b']);
print('<pre>');
print_r($a);
print('<br />');
print_r($b);
print('</pre>');
?>

Array
(
    [a] => a
    =>
)
Array
(
    [a] => a
)

# cat stream


#! /bin/bash

# Write by Neil.xu qq:37391319 email: xurongzhong@gmail.com

# 2008-8-19 we need to monitor streams of LTS channels, so write this script

typeset in in_old dif_in dif_in1 dif_out1
typeset out out_old dif_out

in_old=$(cat /proc/net/dev | grep eth0 | sed 's=^.*:==' | awk '{ print $1 }' )
out_old=$(cat /proc/net/dev | grep eth0 | sed 's=^.*:==' | awk '{ print $9 }')

while true
do
         sleep 1
         in=$(cat /proc/net/dev | grep eth0 | sed 's=^.*:==' | awk '{ print $1 }')
         out=$(cat /proc/net/dev | grep eth0 | sed 's=^.*:==' | awk '{ print $9 }')
         dif_in=$((in-in_old))
         dif_in1=$((dif_in * 8 / 1024 / 1024 ))
         dif_out=$((out-out_old))
         echo " IN: ${dif_in} bytes OUT: ${dif_out} bytes "
         dif_out1=$((dif_out * 8 / 1024 / 1024 ))
         echo "IN: ${dif_in1} mbps OUT: ${dif_out1} mbps"
         in_old=${in}
         out_old=${out}
done