3rd Linux Common Commands (5) _ Network command

7. Network Commands

7.1 send message to user to Ctr+d save end

(1) Write command

Command name	Write
Command path	/user/bin/write
Execute permissions	All Users
Grammar	Write < user name >

(2) Precautions

① when the input is wrong, you can press the ctr+ backspace key to delete the character (not the backspace)

② can only be sent to online users

(3) Application example: $write TestUser then enter the content, and finally press Ctrl+d to send and end

7.2 send a broadcast message

(1) Wall command

Command name	Wall (English intent: Write All)
Command path	/user/bin/wall
Execute permissions	All Users
Grammar	Wall [message]

(2) Precautions

① will receive the message when it is sent

② can only be sent to online users

(3) Application example: $wall I Love you!

7.3 Test network Connectivity

(1) Ping command

Command name	Ping
Command path	/bin/ping
Execute permissions	All Users
Grammar	ping [options] IP address -C: Specify the number of times to send

(2) Application example: $ping-C 4 192.168.32.100//Only PING4 times

7.4 Viewing and setting network card information

(1) Ifconfig command

Command name	Ifconfig (literal:interfAce configure)
Command path	/sbin/ifconfig
Execute permissions	Root
Grammar	Ifconfig NIC name IP address

(2) Application examples:

① View network card information: #ifconfig

② changing the NIC IP, mask

A. Immediate effect: #ifconfig192.168. 32.100 255.255. 255.0 B. Restart effective: #vim   /etc/sysconfig/network-scripts/ifcfg-eth0                  bootproto=static                  ipaddr=192.168 . 32.100                   NETMASK=255.255. 255.0 Restart                  network card: #services Network restart

③ Modifying the default gateway

192.168. 32.1  /etc/sysconfig/network                 GATEWAY=192.168.  32.1

④ modifying DNS

Restart effective: vim/etc/resolv.conf              202.96.  134.133

7.5 lists user information currently logged into the system with the past

(1) Last Order

Command name	Last
Command path	/usr/bin/last
Execute permissions	All Users
Grammar	Last

(2) Application Example: $last

7.6 check when a user last logged in

(1) Lastlog command

Command name	Lastlog
Command path	/usr/bin/lastlog
Execute permissions	All Users
Grammar	Lastlog

(2) Application examples:

① #lastlog

② viewing login information for a specified user

$lastlog –u 502//502 of which represents the UID of a user (available $id testuser view)

7.7 show the path between packets to the host

(1) traceroute command

Command name	Traceroute
Command path	/bin/traceroute
Execute permissions	All Users
Grammar	Traceroutera

(2) Application examples:

①# traceroute-i www.baidu.com//When using NAT mode to surf the internet

②# traceroute www.baidu.com//using bridge mode when surfing the Internet

7.8 Display Network-related information

(1) Netstat command

Command name	Netstat
Command path	/bin/netstat
Execute permissions	All Users
Grammar	netstat [options] -T:TCP protocol -U:UDP protocol -L: Monitor -R: Routing -N: Display IP and port number

(2) Application examples:

　① View Native Listener port: #netstat-tlun

② View all network connections for this computer: #netstat –an

③ View Native routing table: #netstat –rn

7.9 mount Command

(1) Mount command

Command name	Mount
Command path	/bin/mount
Execute permissions	All Users
Grammar	Mount [-T file system ] device file name mount point

(2) Application examples:

　① Mount Optical Drive:

mkdir /tmp/Mount-t iso9660/dev/sr0/tmp/cdrom   (where,-  T iso9660 can also be omitted)ls /tmp/cdrom

　　② unmount Optical drive:#umount/dev/sr0 (/dev/sr0 is the file name of the optical drive device )

3rd Linux Common Commands (5) _ Network command