linux常用基本命令
wc命令
统计指定的文件中的字节数、字数、行数，并将统计结果显示输出。如果没有给出文件名，则从标准输入读取。wc同时也给出所指文件的总统计数
语法：wc [选项] [文件名]
-c：统计字节数；
-l：统计行数；
-m：统计字符数。这个标志不能与-c一起使用；
-w：统计字数。一个字被定义为空白、跳格或者换行字符分割的字符串；
-L：打印最长行的长度
[root@localhost wc]# cat test.txt hnlinux peida.cnblogs.com ubuntu ubuntu linux redhat Redhat linuxmint [root@localhost wc]# wc test.txt 7 8 76 test.txt [root@localhost wc]# wc -l test.txt 7 test.txt [root@localhost wc]# wc -c test.txt 76 test.txt [root@localhost wc]# wc -w test.txt 8 test.txt [root@localhost wc]# wc -m test.txt 76 test.txt [root@localhost wc]# wc -L test.txt 18 test.txt [root@localhost wc]#
uptime命令
uptime命令能够打印系统运行了多长时间和系统平均负载。uptime命令可以显示的信息依次是：现在时间、系统已经运行了多长时间、目前有多少登录用户、系统过去的1分钟、5分钟和15分钟内的平均负载。
语法：uptime [选项]
-V：显示指令的版本信息
[root@localhost wc]# uptime -V uptime from procps-ng 3.3.10 [root@localhost wc]#
使用uptime命令查看系统负载：
[root@localhost wc]# uptime 22:16:12 up 4:26, 1 user, load average: 0.08, 0.04, 0.05 [root@localhost wc]#
显示内容说明：
22:16:12//系统当前时间
up 4:26//主机已经运行时间，时间越大，说明你的机器越稳定
1 user//用户连接数，是总连接数而不是用户数
load average: 0.08, 0.04, 0.05//系统平均负载，统计最近1,5,15分钟的系统平均负载
cut命令
cut命令从文件的每一行剪切字节、字符和字段并将这些字节、字符和字段写入标准输出。
语法：cut [-bn] [file] 或 cut [-c] [file] 或 cut [-df] [file]
如果不指定file参数，cut命令将读取标准输入。必须制定-b、-c或-f标志之一。
-b：已字节为单位进行分割。这些字节位置将忽略多字节字符边界，除非也制定了-n标志。
-c：已字符为单位进行分割。
-d：自定义分隔符，默认为制表符。
-f：与-d一起使用，制定显示哪个区域。
-n：取消分割多字节字符。仅和-b标志一起使用。如果字符的最后一个字节落在由-b标志的List参数指定的<br/>范围之内，该字符将被写出；否则，该字符被排除。
cut命令可将一串字符作为列来显示，字符字段的记法：
N-：从第N个字节、字符、字段到结尾。
N-M：从第N个字节、字符、字段到第M个（包括M在内）字节、字符、字段。
-M：从第1个字节、字符、字段到第M个（包括M在内）字节、字符、字段。
以/etc/passwd的前5行内容为例：
[root@localhost wc]# head -n 5 /etc/passwd root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin [root@localhost wc]#
截取用户名：-d来设置分隔符为“:”，然后用-f来设置截取第一个域：
[root@localhost wc]# head -n 5 /etc/passwd | cut -d ':' -f 1 root bin daemon adm lp [root@localhost wc]#
截取第1,3到5字段：
[root@localhost wc]# head -n 5 /etc/passwd | cut -d ':' -f 1,3-5 root:0:0:root bin:1:1:bin daemon:2:2:daemon adm:3:4:adm lp:4:7:lp [root@localhost wc]#
截取1到3个字符：
[root@localhost wc]# head -n 5 /etc/passwd | cut -c 1-3 roo bin dae adm lp: [root@localhost wc]#
截取前2个字符：
[root@localhost wc]# head -n 5 /etc/passwd | cut -c -2 ro bi da ad lp [root@localhost wc]#
截取第5个字符开始到结尾：
[root@localhost wc]# head -n 5 /etc/passwd | cut -c 5- :x:0:0:root:/root:/bin/bash x:1:1:bin:/bin:/sbin/nologin on:x:2:2:daemon:/sbin:/sbin/nologin x:3:4:adm:/var/adm:/sbin/nologin :4:7:lp:/var/spool/lpd:/sbin/nologin [root@localhost wc]#
netstat命令
netstat是一个告诉我们系统中所有tcp/udp/unix socket连接状态的命令行工具。它会列出所有已连接或等待连接状态的连接。该工具在识别某个应用监听哪个端口时特别有用，我们也能用它来判断某个应用是否正常的在监听某个端口。
netstat命令还能显示其他各种各样的网络相关信息，例如路由表，网卡统计信息，虚假连接以及多播成员等。
1）、检查所有的连接
使用a选项可以列出系统中的所有连接。
[root@localhost wc]# netstat -a Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN tcp 0 52 localhost.localdoma:ssh 10.0.30.1:lnvmaps ESTABLISHED tcp6 0 0 [::]:mysql [::]:* LISTEN tcp6 0 0 [::]:ssh [::]:* LISTEN tcp6 0 0 localhost:smtp [::]:* LISTEN raw6 0 0 [::]:ipv6-icmp [::]:* 7 Active UNIX domain sockets (servers and established) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 13568 /run/lvm/lvmetad.socket unix 2 [ ] DGRAM 13571 /run/systemd/shutdownd unix 3 [ ] DGRAM 8710 /run/systemd/notify unix 2 [ ] DGRAM 8712 /run/systemd/cgroups-agent unix 2 [ ACC ] STREAM LISTENING 21355 public/showq unix 2 [ ACC ] STREAM LISTENING 8730 /run/systemd/journal/stdout unix 5 [ ] DGRAM 8733 /run/systemd/journal/socket
这会显示系统所有的tcp、udp以及unix连接。
2）、检查所有tcp/udp/unix socket连接
使用t选项只列出tcp连接。
[root@localhost wc]# netstat -at Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN tcp 0 52 localhost.localdoma:ssh 10.0.30.1:lnvmaps ESTABLISHED tcp6 0 0 [::]:mysql [::]:* LISTEN tcp6 0 0 [::]:ssh [::]:* LISTEN tcp6 0 0 localhost:smtp [::]:* LISTEN [root@localhost wc]#
类似的，使用u选项只列出udp连接。
[root@localhost wc]# netstat -au Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State [root@localhost wc]#
使用x选项只列出unix socket连接。
[root@localhost wc]# netstat -ax Active UNIX domain sockets (servers and established) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 13568 /run/lvm/lvmetad.socket unix 2 [ ] DGRAM 13571 /run/systemd/shutdownd unix 3 [ ] DGRAM 8710 /run/systemd/notify unix 2 [ ] DGRAM 8712 /run/systemd/cgroups-agent unix 2 [ ACC ] STREAM LISTENING 21355 public/showq unix 2 [ ACC ] STREAM LISTENING 8730 /run/systemd/journal/stdout unix 5 [ ] DGRAM 8733 /run/systemd/journal/socket unix 12 [ ] DGRAM 8735 /dev/log unix 2 [ ACC ] SEQPACKET LISTENING 13622 /run/udev/control unix 2 [ ACC ] STREAM LISTENING 21620 /tmp/mysql.sock unix 2 [ ACC ] STREAM LISTENING 21330 private/trace unix 2 [ ACC ] STREAM LISTENING 21337 private/verify unix 2 [ ACC ] STREAM LISTENING 21343 private/proxymap
3）、同时列出ID/进程名称
使用p选项可以列出连接的同时也显示PID或者进程名称，而且它还能与其他选项连用。
[root@localhost wc]# netstat -ap Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN 992/sshd tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN 1563/master tcp 0 52 localhost.localdoma:ssh 10.0.30.1:lnvmaps ESTABLISHED 1813/sshd: root@pts tcp6 0 0 [::]:mysql [::]:* LISTEN 1631/mysqld tcp6 0 0 [::]:ssh [::]:* LISTEN 992/sshd tcp6 0 0 localhost:smtp [::]:* LISTEN 1563/master raw6 0 0 [::]:ipv6-icmp [::]:* 7 686/NetworkManager Active UNIX domain sockets (servers and established) Proto RefCnt Flags Type State I-Node PID/Program name Path unix 2 [ ACC ] STREAM LISTENING 13568 1/systemd /run/lvm/lvmetad.socket unix 2 [ ] DGRAM 13571 1/systemd /run/systemd/shutdownd unix 3 [ ] DGRAM 8710 1/systemd /run/systemd/notify unix 2 [ ] DGRAM 8712 1/systemd /run/systemd/cgroups-agent unix 2 [ ACC ] STREAM LISTENING 21355 1563/master public/showq unix 2 [ ACC ] STREAM LISTENING 8730 1/systemd /run/systemd/journal/stdout unix 5 [ ] DGRAM 8733 1/systemd /run/systemd/journal/socket unix 12 [ ] DGRAM 8735 1/systemd /dev/log unix 2 [ ACC ] SEQPACKET LISTENING 13622 1/systemd /run/udev/control unix 2 [ ACC ] STREAM LISTENING 21620 1631/mysqld /tmp/mysql.sock unix 2 [ ACC ] STREAM LISTENING 21330 1563/master private/trace unix 2 [ ACC ] STREAM LISTENING 21337 1563/master private/verify unix 2 [ ACC ] STREAM LISTENING 21343 1563/master private/proxymap unix 2 [ ACC ] STREAM LISTENING 21346 1563/master private/proxywrite unix 2 [ ACC ] STREAM LISTENING 21349 1563/master private/smtp unix 2 [ ACC ] STREAM LISTENING 21352 1563/master private/relay unix 2 [ ACC ] STREAM LISTENING 21358 1563/master private/error unix 2 [ ACC ] STREAM LISTENING 21361 1563/master private/retry
4）、列出端口号而不是服务名
使用n选项可以加快输出，它不会执行任何反向查询，而是直接输出数字。由于无需查询，因此结果输出会很快。
[root@localhost wc]# netstat -an Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp 0 52 10.0.30.102:22 10.0.30.1:2284 ESTABLISHED tcp6 0 0 :::3306 :::* LISTEN tcp6 0 0 :::22 :::* LISTEN tcp6 0 0 ::1:25 :::* LISTEN raw6 0 0 :::58 :::* 7 Active UNIX domain sockets (servers and established) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 13568 /run/lvm/lvmetad.socket unix 2 [ ] DGRAM 13571 /run/systemd/shutdownd unix 3 [ ] DGRAM 8710 /run/systemd/notify unix 2 [ ] DGRAM 8712 /run/systemd/cgroups-agent unix 2 [ ACC ] STREAM LISTENING 21355 public/showq unix 2 [ ACC ] STREAM LISTENING 8730 /run/systemd/journal/stdout unix 5 [ ] DGRAM 8733 /run/systemd/journal/socket unix 12 [ ] DGRAM 8735 /dev/log unix 2 [ ACC ] SEQPACKET LISTENING 13622 /run/udev/control unix 2 [ ACC ] STREAM LISTENING 21620 /tmp/mysql.sock unix 2 [ ACC ] STREAM LISTENING 21330 private/trace unix 2 [ ACC ] STREAM LISTENING 21337 private/verify unix 2 [ ACC ] STREAM LISTENING 21343 private/proxymap unix 2 [ ACC ] STREAM LISTENING 21346 private/proxywrite unix 2 [ ACC ] STREAM LISTENING 21349 private/smtp unix 2 [ ACC ] STREAM LISTENING 21352 private/relay
5）、只输出监听端口
使用l选项只输出监听端口。它不能与a选项连用，因为a会输出所有端口。
[root@localhost wc]# netstat -l Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN tcp6 0 0 [::]:mysql [::]:* LISTEN tcp6 0 0 [::]:ssh [::]:* LISTEN tcp6 0 0 localhost:smtp [::]:* LISTEN raw6 0 0 [::]:ipv6-icmp [::]:* 7 Active UNIX domain sockets (only servers) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 13568 /run/lvm/lvmetad.socket unix 2 [ ACC ] STREAM LISTENING 21355 public/showq unix 2 [ ACC ] STREAM LISTENING 8730 /run/systemd/journal/stdout unix 2 [ ACC ] SEQPACKET LISTENING 13622 /run/udev/control unix 2 [ ACC ] STREAM LISTENING 21620 /tmp/mysql.sock unix 2 [ ACC ] STREAM LISTENING 21330 private/trace unix 2 [ ACC ] STREAM LISTENING 21337 private/verify unix 2 [ ACC ] STREAM LISTENING 21343 private/proxymap unix 2 [ ACC ] STREAM LISTENING 21346 private/proxywrite unix 2 [ ACC ] STREAM LISTENING 21349 private/smtp unix 2 [ ACC ] STREAM LISTENING 21352 private/relay unix 2 [ ACC ] STREAM LISTENING 21358 private/error unix 2 [ ACC ] STREAM LISTENING 21361 private/retry unix 2 [ ACC ] STREAM LISTENING 21364 private/discard unix 2 [ ACC ] STREAM LISTENING 21367 private/local unix 2 [ ACC ] STREAM LISTENING 21370 private/virtual unix 2 [ ACC ] STREAM LISTENING 21373 private/lmtp unix 2 [ ACC ] STREAM LISTENING 21377 private/anvil unix 2 [ ACC ] STREAM LISTENING 21380 private/scache unix 2 [ ACC ] STREAM LISTENING 13436 /run/systemd/private unix 2 [ ACC ] STREAM LISTENING 16805 /run/dbus/system_bus_socket unix 2 [ ACC ] STREAM LISTENING 21297 public/pickup unix 2 [ ACC ] STREAM LISTENING 21302 public/cleanup unix 2 [ ACC ] STREAM LISTENING 21305 public/qmgr unix 2 [ ACC ] STREAM LISTENING 21340 public/flush unix 2 [ ACC ] STREAM LISTENING 21309 private/tlsmgr unix 2 [ ACC ] STREAM LISTENING 21321 private/rewrite unix 2 [ ACC ] STREAM LISTENING 21324 private/bounce unix 2 [ ACC ] STREAM LISTENING 21327 private/defer unix 2 [ ACC ] STREAM LISTENING 13761 /run/lvm/lvmpolld.socket unix 2 [ ACC ] STREAM LISTENING 17657 /var/run/vmware/guestServicePipe [root@localhost wc]#
6）、输出网络状态
使用s选项输出每个协议的统计信息，包括接收/发送的包数量。
[root@localhost wc]# netstat -s
Ip:
4688 total packets received
0 forwarded
0 incoming packets discarded
4408 incoming packets delivered
4110 requests sent out
Icmp:
818 ICMP messages received
409 input ICMP message failed.
ICMP input histogram:
destination unreachable: 818
818 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 818
IcmpMsg:
InType3: 818
OutType3: 818
Tcp:
409 active connections openings
1 passive connection openings
409 failed connection attempts
0 connection resets received
1 connections established
3574 segments received
2888 segments send out
409 segments retransmited
0 bad segments received.
0 resets sent
Udp:
16 packets received
0 packets to unknown port received.
0 packet receive errors
16 packets sent
0 receive buffer errors
0 send buffer errors
UdpLite:
TcpExt:
14 delayed acks sent
1 delayed acks further delayed because of locked socket
1041 packet headers predicted
556 acknowledgments not containing data payload received
1386 predicted acknowledgments
409 other TCP timeouts
TCPRcvCoalesce: 1
TCPSpuriousRtxHostQueues: 760
TCPSynRetrans: 409
TCPOrigDataSent: 2440
IpExt:
InBcastPkts: 280
InOctets: 374032
OutOctets: 465867
InBcastOctets: 27427
InNoECTPkts: 4688
[root@localhost wc]#
7）、输出网卡状态
使用i选项只显示网卡的统计信息。
[root@localhost wc]# netstat -i Kernel Interface table Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg ens33 1500 4152 0 0 0 5224 0 0 0 BMRU lo 65536 822 0 0 0 822 0 0 0 LRU [root@localhost wc]#
8）、显示多播组信息
使用g选项输出IPV4以及IPV6的多播信息。
[root@localhost wc]# netstat -g IPv6/IPv4 Group Memberships Interface RefCnt Group --------------- ------ --------------------- lo 1 all-systems.mcast.net ens33 1 all-systems.mcast.net lo 1 ff02::1 lo 1 ff01::1
9）、显示网络路由信息
使用r选项输出网络路由信息。
[root@localhost wc]# netstat -r Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface default gateway 0.0.0.0 UG 0 0 0 ens33 10.0.30.0 0.0.0.0 255.255.254.0 U 0 0 0 ens33 [root@localhost wc]#
10）、持续输出
使用c选项持续输出信息。
[root@localhost wc]# netstat -c
