Common Linux commands (6)-network communication commands

1. Command name: Write

Execution permission: All Users

Function Description: sends a message to another user, ending with Ctrl + D.

Syntax: Write <User Name>

 
Root sends information to the luxh user [root@ Localhost ~]#Write luxhWrite: luxh is loggedInMore than once; writing to PTS/1Hello, luxh, I am root, the information that luxh receives is [luxh@ Localhost ~] $Message from luxh@ Localhost. localdomain (as root) on pts/0 at 05:17... Hello, luxh, I am Root
 

The root user sends a message to the luxh user. The luxh user must have logged on; otherwise, the message cannot be sent.

 

2. Command name: Wall

Execution permission: All Users

Function Description: broadcasts information to all users.

Syntax: Wall [Message] [file name]

 
Root sends information to all login users [root@ Localhost ~]#Wall happy new yearBroadcast message from Root@ Localhost. localdomain (pts/0) (Thu Nov 22 05:27:49 2012): Happy New Year [root@ Localhost ~]#The logged-on user can receive the [luxh@ Localhost ~] $Broadcast message from Root@ Localhost. localdomain (pts/0) (Thu Nov 22 05:27:49 2012): Happy New Year
 

 

3. Command name: Ping

Execution permission: Root

Function Description: test network connectivity.

Syntax: Ping [Option] IP Address

In Linux, ping the ID directly and press Ctrl + C to terminate the command. Otherwise, Ping
[Root @ localhost ~] #  Ping 192.168.1.1 Ping 192.168.1.1 (192.168.1.1) 56 (84 ) Bytes of data. 64 bytes from 192.168.1.1: icmp_seq = 1 TTL = 128 time = 6.66 MS 64 bytes from 192.168.1.1: icmp_seq = 2 TTL = 128 time = 6.63 MS 64 bytes from 192.168.1.1: icmp_seq = 3 TTL = 128 time = 3.13 MS 64 bytes from 192.168.1.1: icmp_seq = 4 TTL = 128 time = 4.55 MS 64 bytes from 192.168.1.1: icmp_seq = 5 TTL = 128 time = 6.69 MS 64 bytes from 192.168.1.1: icmp_seq = 6 TTL = 128 time = 5.90 MS 64 bytes from 192.168.1.1: icmp_seq = 7 TTL = 128 time = 2.77 MS 64 bytes from 192.168.1.1: icmp_seq = 8 TTL = 128 time = 2.75 MS 64 bytes from 192.168.1.1: icmp_seq = 9 TTL = 128 time = 5.41 MS 64 bytes from 192.168.1.1: icmp_seq = 10 TTL = 128 time = 7.52 MS

Use-C to specify the number of Ping times
[Luxh @ localhost ~] $ Ping-C 4 192.168.1.1Ping192.168.1.1 (192.168.1.1) 56 (84) Bytes of data.64 bytes from 192.168.1.1: icmp_seq = 1 TTL = 128 time = 6.49MS64 bytes from 192.168.1.1: icmp_seq = 2 TTL = 128 time = 5.42MS64 bytes from 192.168.1.1: icmp_seq = 3 TTL = 128 time = 2.46MS64 bytes from 192.168.1.1: icmp_seq = 4 TTL = 128 time = 3.69MS--- 192.168.1.1 Ping statistics --- 4 packets transmitted, 4 encrypted ed, 0%Packet Loss, time 3010 msrtt min/AVG/max/mdev = 2.464/4.520/6.498/1.551MS [luxh@ Localhost ~] $
 

 

Use-s to specify the size of the sending package, up to 65507 bytes
[Root @ localhost ~]#Ping-C 4-s 1024 192.168.1.1Ping 192.168.1.1 (192.168.1.1) 1024 (1052) Bytes of data.1032 bytes from 192.168.1.1: icmp_seq = 1 TTL = 128 time = 6.67MS1032 bytes from 192.168.1.1: icmp_seq = 2 TTL = 128 time = 4.21MS1032 bytes from 192.168.1.1: icmp_seq = 3 TTL = 128 time = 9.06MS1032 bytes from 192.168.1.1: icmp_seq = 4 TTL = 128 time = 5.09MS--- 192.168.1.1 Ping statistics --- 4 packets transmitted, 4 encrypted ed, 0%Packet Loss, time 3010 msrtt min/AVG/max/mdev = 4.212/6.262/9.064/1.845MS [root@ Localhost ~]# 
 

4. Command name: ifconfig

Execution permission: Root

Function Description: View network settings.

Syntax: ifconfig [-A] [Nic device ID]

-A: displays information about all network adapters (this information can be omitted in Linux and cannot be omitted in UNIX)

[Root @ localhost ~] #  Ifconfig Eth0 link encap: Ethernet hwaddr 00: 0C: 29: 4C: 63 : 3E Inet ADDR: 192.168.0.102 bcast: 192.168.0.255 mask: 255.255.255.0 Inet6 ADDR: fe80 : 20c: 29ff: fe4c: 633e/64Scope: link up broadcast running Multicast MTU: 1500 Metric: 1 RX packets: 4238 errors: 0 dropped: 0 overruns: 0 frame: 0 TX packets: 3578 errors: 0 dropped: 0 overruns: 0 carrier: 0 Collisions: 0 txqueuelen: 1000 RX Bytes: 4560042 (4.3 MIB) TX Bytes: 299603 (292.5 Kib) interrupt: 19 base address: 0x2024 Lo link encap: local loopback Inet ADDR: 127.0.0.1 mask: 255.0.0.0 Inet6 ADDR: : 1/128Scope: Host up loopback running MTU: 16436 Metric: 1 RX packets: 8 errors: 0 dropped: 0 overruns: 0 frame: 0 TX packets: 8 errors: 0 dropped: 0 overruns: 0 carrier: 0 Collisions: 0 txqueuelen: 0 RX Bytes: 480 (480.0 B) TX Bytes: 480 (480.0 B)

Eth0 is the actual physical Nic, and lo is the virtual loopback address Nic.

 
Temporarily change the IP address, which is invalid after restart [root@ Localhost ~]#Ifconfig eth0 192.168.1.5