nstat
===
nstat 是一个简单的监视内核的 SNMP 计数器和网络接口状态的实用工具。
## 补充说明
大多数命令行用户都熟悉 netstat ，这是 net-tools 软件包中的命令。目前新版本中 net-tools 软件包几乎完全被弃用，取而代之的是 ip 命令套件，而 nstat 属于新软件包。
### 语法
```s
nstat [OPTION] [ PATTERN [ PATTERN ] ]
```
### 选项
```shell
-h：显示帮助信息；
-V：显示指令版本信息；
-z：转储零计数器。默认情况下不显示它们；
-r：清零历史统计；
-n：不显示任何内容，仅更新历史；
-a：显示计数器的绝对值；
-d：以守护进程模式运行并收集统计数据
-s：不更新历史；
-j：JSON格式输出。
```
### 实例
直接输入以查询网络接口状态，以下展示了 IPv4，IPv6，TCP，UDP，ICMP 的统计数据：
```shell
nstat
#kernel
IpInReceives 769152 0.0
IpInAddrErrors 1 0.0
IpInDelivers 769146 0.0
IpOutRequests 764236 0.0
IpOutDiscards 20 0.0
IpOutNoRoutes 1 0.0
IcmpInMsgs 92 0.0
IcmpInDestUnreachs 92 0.0
IcmpOutMsgs 94 0.0
IcmpOutDestUnreachs 94 0.0
IcmpMsgInType3 92 0.0
IcmpMsgOutType3 94 0.0
TcpActiveOpens 1786 0.0
TcpPassiveOpens 142 0.0
TcpAttemptFails 11 0.0
TcpEstabResets 72 0.0
TcpInSegs 756827 0.0
TcpOutSegs 802908 0.0
TcpRetransSegs 767 0.0
TcpOutRsts 702 0.0
UdpInDatagrams 12075 0.0
UdpNoPorts 82 0.0
UdpOutDatagrams 7045 0.0
UdpIgnoredMulti 70 0.0
Ip6InReceives 5005 0.0
Ip6InDelivers 5005 0.0
Ip6OutRequests 131 0.0
Ip6OutDiscards 2 0.0
Ip6OutNoRoutes 959 0.0
Ip6InMcastPkts 4999 0.0
Ip6OutMcastPkts 125 0.0
Ip6InOctets 797462 0.0
Ip6OutOctets 16421 0.0
Ip6InMcastOctets 797030 0.0
Ip6OutMcastOctets 15949 0.0
Ip6InNoECTPkts 5005 0.0
Icmp6InMsgs 3 0.0
Icmp6OutMsgs 51 0.0
Icmp6InNeighborAdvertisements 1 0.0
Icmp6InMLDv2Reports 2 0.0
Icmp6OutRouterSolicits 11 0.0
Icmp6OutNeighborSolicits 4 0.0
Icmp6OutMLDv2Reports 36 0.0
Icmp6InType136 1 0.0
Icmp6InType143 2 0.0
Icmp6OutType133 11 0.0
Icmp6OutType135 4 0.0
Icmp6OutType143 36 0.0
Udp6InDatagrams 4998 0.0
Udp6OutDatagrams 76 0.0
TcpExtTW 385 0.0
TcpExtPAWSEstab 1 0.0
TcpExtDelayedACKs 37133 0.0
TcpExtDelayedACKLocked 57 0.0
TcpExtDelayedACKLost 456 0.0
TcpExtTCPHPHits 417717 0.0
TcpExtTCPPureAcks 34186 0.0
TcpExtTCPHPAcks 222980 0.0
TcpExtTCPSACKReorder 1 0.0
TcpExtTCPLossUndo 194 0.0
TcpExtTCPLostRetransmit 169 0.0
TcpExtTCPSlowStartRetrans 1 0.0
TcpExtTCPTimeouts 494 0.0
TcpExtTCPLossProbes 309 0.0
TcpExtTCPBacklogCoalesce 571 0.0
TcpExtTCPDSACKOldSent 281 0.0
TcpExtTCPDSACKRecv 281 0.0
TcpExtTCPAbortOnData 13 0.0
TcpExtTCPAbortOnClose 30 0.0
TcpExtTCPDSACKIgnoredOld 1 0.0
TcpExtTCPDSACKIgnoredNoUndo 258 0.0
TcpExtTCPSackShiftFallback 1 0.0
TcpExtTCPRcvCoalesce 18314 0.0
TcpExtTCPFastOpenActiveFail 2 0.0
TcpExtTCPSpuriousRtxHostQueues 11 0.0
TcpExtTCPAutoCorking 1684 0.0
TcpExtTCPFromZeroWindowAdv 2 0.0
TcpExtTCPToZeroWindowAdv 2 0.0
TcpExtTCPSynRetrans 479 0.0
TcpExtTCPOrigDataSent 359814 0.0
TcpExtTCPHystartTrainDetect 13 0.0
TcpExtTCPHystartTrainCwnd 550 0.0
TcpExtTCPKeepAlive 18 0.0
TcpExtTCPDelivered 361695 0.0
TcpExtTCPZeroWindowDrop 1 0.0
TcpExtTcpTimeoutRehash 494 0.0
TcpExtTcpDuplicateDataRehash 2 0.0
TcpExtTCPDSACKRecvSegs 281 0.0
IpExtInNoRoutes 3 0.0
IpExtInMcastPkts 5392 0.0
IpExtOutMcastPkts 221 0.0
IpExtInBcastPkts 70 0.0
IpExtOutBcastPkts 10 0.0
IpExtInOctets 2100280442 0.0
IpExtOutOctets 226760631 0.0
IpExtInMcastOctets 746608 0.0
IpExtOutMcastOctets 27565 0.0
IpExtInBcastOctets 5674 0.0
IpExtOutBcastOctets 778 0.0
IpExtInNoECTPkts 1885871 0.0
```
