Linux Learning Notes (8) network commands for common Linux commands

(1) Write

The Write command is used to send messages to the specified user, Ctrl+d save ends, and the path is/usr/bin/write, in the syntax format:

Write [user name]

Note: Can only be sent to online users.

Example: New WS user, root remote sends hello information to WS remote end.

Root side:

[[email protected] cdrom]# write Wshello

WS-Side:

[[Email protected] ~] $Message from [e-mail protected] on PTS/1 at 03:58 ... helloeof

Where EOF indicates the end.

(2) Wall

The wall command is used to send broadcast messages, the English original is write all, where the path is/usr/bin/wall, and its syntax is:

Wall [message]

Example: Send a hello message to all online users at the root remote end:

Root side:

[[email protected] cdrom]# Wall Hello[[email protected] cdrom] #Broadcast message from [email protected] (PTS/1) (Fri jan
   2 04:05:08): Hello

WS-Side:

[[Email protected] ~] $Broadcast message from [email protected] (PTS/1) (Fri Jan  2 04:05:08): Hello

(3) Ping

The ping command is used to test network connectivity, where the path is/bin/ping, in the syntax format:

Ping option IP Address

Where-c option specifies the number of times to send

For example: Test the loopback address 127.0.0.1, set the number of times to 3:

[Email protected] cdrom]# ping-c 3 127.0.0.1PING 127.0.0.1 (127.0.0.1) (+) bytes of data.64 bytes from 127.0.0.1:ICM P_seq=1 ttl=64 time=0.274 ms64 bytes from 127.0.0.1:icmp_seq=2 ttl=64 time=0.072 ms64 bytes from 127.0.0.1:icmp_seq=3 tt l=64 time=0.070 ms---127.0.0.1 PING statistics---3 packets transmitted, 3 received, 0% packet loss, time 1999msrtt min/ Avg/max/mdev = 0.070/0.138/0.274/0.096 ms

(4) Ifconfig

The Ifconfig command is used to view and set the network card information, the English original intent is interface configure, where the path is/sbin/ifconfig, the syntax format is:

Ifconfig Network card IP address

Note: Ifconfig only temporarily sets the IP address, and the configuration is eliminated the next time the system is restarted.

(5) Mail

The Mail command is used to view and send e-mail messages, characterized by the user not being able to send them online, where the path is/bin/mail, with the syntax in the following format:

Mail [user name]

Example: Root remote end sending mail to WS remote

Root Remote side:

[[Email protected] cdrom]# mail Wssubject:hellohello I am wseot[[email protected] cdrom]#

WS Remote End:

[Email protected] ~]$ mailheirloom Mail version 12.4 7/29/08.  Type? For help. " /var/spool/mail/ws ": 1 message 1 new>n  1 root                  Fri Jan  2 04:17  18/606   " Hello "&

Enter 1 to view the message:

& 1Message  1:from [email protected]  Fri Jan  2 04:17:44 2015return-path: <[email protected]> x-original-to:wsdelivered-to: [Email Protected]date:fri, 04:17:43 +0800to: [Email protected]subject:hellous Er-agent:heirloom MAILX 12.4 7/29/08content-type:text/plain; Charset=us-asciifrom: [Email protected] (root) status:r hello i am ws &

(6) Last

The last command lists user information that is currently logged into the system, with a path of/usr/bin/last, in the syntax format:

Last

Cases:

[[email protected] cdrom]# lastws pts/0 110.13.4.109 Fri Jan 2 03:57 still logged in WS pts/ 0 110.13.4.109 Fri Jan 2 03:56-03:57 (00:00) ws pts/0 110.13.4.109 Thu Jan 1 22:59-00:       01:03 root PTS/1 110.13.4.109 Thu Jan 1 18:44 still logged in root pts/0 110.13.4.109    Thu Jan 1 18:38-20:49 (02:11) root tty1 Thu Jan 1 18:36 still logged in reboot System Boot 2.6.32-431.el6.i Thu Jan 1 18:35-04:22 (09:47) root pts/0 110.13.4.109 Thu Jan 1 17: 43-crash (00:51) root tty1 Thu Jan 1 17:41-crash (00:54) reboot system boot 2.6. 32-431.el6.i Thu Jan 1 17:38-04:22 (10:43) root pts/0 110.13.4.236 Tue Oct 20:24-crash (71+21:1  3) Root tty1 Tue Oct 20:23-crash (71+21:15) reboot system boot 2.6.32-431.el6.i Tue Oct 21 18:59-04:22 (72+09: Root pts/0 110.13.4.236 Tue Oct 06:31-06:32 (00:00) root tty1 Tue Oct 06:29-crash (12:30pm) reboot system boot 2.6.32-431.el6.i Tue Oct 06:27-04:22 (72+21:54) wtmp begins T UE OCT 21 06:27:29 2014

(7) Lastlog

The Lastlog command is used to check the last logon time for a particular user, where the path is/usr/bin/lastlog, with the syntax in the following format:

Lastlog

Example: Lastlog or Last-u 500

[Email protected] cdrom]# lastlog-u 500Username       Port from             latestws             pts/0      110.13.4.109 Fri Jan  2 03:57:07 +0800 2015

(8) Traceroute

The traceroute command is used to display the path information between packets to the host, where the path is/bin/traceroute, with the syntax in the following format:

Traceroute website

(9) Netstat

The netstat command is used to display network-related information, where the path is/bin/netstat, with the syntax in the following format:

netstat [options]

Where the-t option represents the TCP protocol, the-U option represents the UDP protocol,-L for listening,-R for routing, and-n for displaying the IP address and port number.

such as: View the local listening port-----Netstat-tlun

View all network connections on this computer-----netstat-an

View the native routing table-----Netstat-rn.

(Ten) Setup

The Setup command is used to configure the network, which is characterized by a permanent effect, unlike ifconfig, where the path is/usr/bin/setup and its syntax is in the following format:

Setup

Note: This command is a proprietary command of the Red Hat series.

(one) Mount

The Mount command is used for mounting, where the path is/bin/mount, with the syntax in the following format:

Mount [-t file system] device file name mount point

Example: Create a CDROM folder as a mount point in the/mnt directory, then select an ISO image and mount it:

[Email protected] ~]# mkdir/mnt/cdrom[[email protected] ~]# Mount/dev/sr0/mnt/cdrom/mount:block device/dev/sr0 is WR ite-protected, mounting read-only[[email protected] ~]# ls/mnt/cdrom/autorun.inf  Casper  EFI   Isolinux    pics  preseed           ubuntuboot    dists   install  md5sum.txt  pool  readme.diskdefines  Wubi.exe[[email protected] ~]# umount/dev/sr0

Linux Learning Notes (8) network commands for common Linux commands