写作意图：Linux系统自带的netstat在很多时候抓信息会发现耗CPU很高，特别是在做一些监控系统的时候，发现如果使用了netstat，监控系统本身会造成系统负载比较高，因此试着用perl写下，time测试比自带的netstat更快更节省资源，欢迎批评，呵呵。#！/usr/bin/perl # Written by FinalBSD at 2008-11-20. # The netstat original written by C # is expensive to me, so this born. # As long as you retain this notice you # can do whatever you want with this stuff. # If we meet some day, and you think # this stuff is worth it, you can # buy me a beer in return. use strict; use warnings; use Getopt::Std; my $tcp = "/proc/net/tcp"; my $tcp6 = "/proc/net/tcp6"; my $route = "/proc/net/route"; my @tcpState = （ "NULL", "ESTABLISHED" , "SYN_SENT", "SYN_RECV", "FIN_WAIT1", "FIN_WAIT2", "TIME_WAIT", "CLOSE", "CLOSE_WAIT", "LAST_ACK", "LISTEN", "CLOSING" ）; my @routeType = （ "NULL", "U", # UP "G", # Gateway "UG" # UP & Gateway ）; my %opts; getopts（"nhatsrl", \%opts）; if（$opts{h}） { &usage（）; } if（$opts{r}） { &route_info（$route）; exit; } &tcp_info（$tcp）; &tcp_info（$tcp6）; ###################### FUNCTION DEFINITION ########################### ############################# # Get statistics Information ############################ sub tcp_info（$） { my $file = shift; open（FH, $file） or die（"$！"）; my $format = "%-30s %-30s %-10s
"; printf（$format," Local Address"," Foreign Address","State"）; while（<FH>） { next if /local_address/; my @data = split; my $state = $tcpState[hex（$data[3]）]; # Show listening Sockets. if（$opts{l}）{ printf（$format, &hextoint（$data[1]）, &hextoint（$data[2]）, $state） if $state =~ /LIST/; } else { printf（$format, &hextoint（$data[1]）, &hextoint（$data[2]）, $state）; } } close（FH）; } ############################# # Convert hex to int ############################ sub hextoint（$） { my $tmp = shift; my @data; my @ip; my $int; # if have ":", then it"s addr:port,else just port. if（ $tmp =~ /:/ ） { if（ $tmp =~ /FFFF/ ） { @data = split /:/, $tmp; # break it and do convert later. @ip = $data[0] =~ /w{2}/g; foreach my $index （12..15）{ $ip[$index] = hex（$ip[$index]）; } $int = sprintf（"%-5s %d.%d.%d.%d:%d", "tcp6",$ip[15], $ip[14], $ip[13], $ip[12], hex（$data[1]））; } else { @data = split /:/, $tmp; @ip = $data[0] =~ /w{2}/g; foreach my $index （0..3）{ $ip[$index] = hex（$ip[$index]）; } $int = sprintf（"%-s %d.%d.%d.%d:%d", " ",$ip[3], $ip[2], $ip[1], $ip[0], hex（$data[1]））; } } else { @ip = $tmp =~ /w{2}/g; foreach my $index （0..3）{ $ip[$index] = hex（$ip[$index]）; } $int = sprintf（"%d.%d.%d.%d", hex（$ip[3]）, hex（$ip[2]）, hex（$ip[1]）, hex（$ip[0]））; } return $int; } ############################# # Show Kernel route table ############################ sub route_info（$） { my $routefile = shift; open（ROUTE, $routefile） or die （"Can"t open route file！
"）; my $header = "Iface Destination Gateway Flags Genmask
"; printf（"%s", $header）; my $format = "%-5s %-15s %-15s %-5s %-15s
"; while（<ROUTE>） { next if /Iface/; my @line = split; my （$iface, $dest, $gw, $flags, $mask ） = （$line[0], &hextoint（$line[1]）, &hextoint（$line[2]）, hex（$line[3]）, &hextoint（$line[7]））; printf（$format, $iface, $dest, $gw, $routeType[$flags], $mask ）; } close（ROUTE）; } ############################# # Show help information ############################ sub usage { printf（"%s
%-30s
%-30s
%-30s
%-30s
%-30s
%-30s
", "netstat written in Perl by FinalBSD.Copyright（c） 2008.", "-n Show numeric ip and port address.", "-r Display the kernel routing table.", "-a Show both listening and non-listening socktes.", "-t Show only TCP statistics.", "-l Show only listening sockets.", "-h Show help.", ）; exit; }[注意]7个极具危险性的Linux命令Htop：Ubuntu下功能全面的进程查看器[多图]相关资讯 Netstat Perl Linux教程
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