20 useful commands for Linux experts (1)

Thank you for your liking for the first two parts of this article, meiyan and support. In the first part of the article, we discussed the commands for users who only need the necessary knowledge to switch to Linux and linux.

20 useful commands for Linux beginners

In the second article, we discuss the commands required by intermediate users to manage their systems.

20 useful commands for intermediate Linux Users

What about next? In this article, I will explain some commands required to manage Linux servers.

1. Command: ifconfig

Ifconfig is used to configure the network interface information of the resident kernel. Set the network adapter information when the system starts. Later, it is usually used only during debugging or when the system needs to be adjusted.

Check active network adapters

 
 

  
  
[avishek@tecmint ~]$ ifconfig 
  
  
eth0      Link encap:Ethernet  HWaddr 40:2C:F4:EA:CF:0E 
  
  
inet addr:192.168.1.3  Bcast:192.168.1.255  Mask:255.255.255.0 
  
  
inet6 addr: fe80::422c:f4ff:feea:cf0e/64 Scope:Link 
  
  
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1 
  
  
RX packets:163843 errors:0 dropped:0 overruns:0 frame:0 
  
  
TX packets:124990 errors:0 dropped:0 overruns:0 carrier:0 
  
  
collisions:0 txqueuelen:1000 
  
  
RX bytes:154389832 (147.2 MiB)  TX bytes:65085817 (62.0 MiB) 
  
  
Interrupt:20 Memory:f7100000-f7120000 
  
  
lo        Link encap:Local Loopback 
  
  
inet addr:127.0.0.1  Mask:255.0.0.0 
  
  
inet6 addr: ::1/128 Scope:Host 
  
  
UP LOOPBACK RUNNING  MTU:16436  Metric:1 
  
  
RX packets:78 errors:0 dropped:0 overruns:0 frame:0 
  
  
TX packets:78 errors:0 dropped:0 overruns:0 carrier:0 
  
  
collisions:0 txqueuelen:0 
  
  
RX bytes:4186 (4.0 KiB)  TX bytes:4186 (4.0 KiB) 
 
 

Check all network adapters

The-a parameter is used to display the details of all network adapters, including those that are disabled.

 
 

  
  
[avishek@tecmint ~]$ ifconfig -a 
  
  
eth0      Link encap:Ethernet  HWaddr 40:2C:F4:EA:CF:0E 
  
  
inet addr:192.168.1.3  Bcast:192.168.1.255  Mask:255.255.255.0 
  
  
inet6 addr: fe80::422c:f4ff:feea:cf0e/64 Scope:Link 
  
  
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1 
  
  
RX packets:163843 errors:0 dropped:0 overruns:0 frame:0 
  
  
TX packets:124990 errors:0 dropped:0 overruns:0 carrier:0 
  
  
collisions:0 txqueuelen:1000 
  
  
RX bytes:154389832 (147.2 MiB)  TX bytes:65085817 (62.0 MiB) 
  
  
Interrupt:20 Memory:f7100000-f7120000 
  
  
lo        Link encap:Local Loopback 
  
  
inet addr:127.0.0.1  Mask:255.0.0.0 
  
  
inet6 addr: ::1/128 Scope:Host 
  
  
UP LOOPBACK RUNNING  MTU:16436  Metric:1 
  
  
RX packets:78 errors:0 dropped:0 overruns:0 frame:0 
  
  
TX packets:78 errors:0 dropped:0 overruns:0 carrier:0 
  
  
collisions:0 txqueuelen:0 
  
  
RX bytes:4186 (4.0 KiB)  TX bytes:4186 (4.0 KiB) 
  
  
virbr0    Link encap:Ethernet  HWaddr 0e:30:a3:3a:bf:03 
  
  
inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0 
  
  
UP BROADCAST MULTICAST  MTU:1500  Metric:1 
  
  
RX packets:0 errors:0 dropped:0 overruns:0 frame:0 
  
  
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 
  
  
collisions:0 txqueuelen:0 
  
  
RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B) 
 
 

Disable a network adapter

 
 

  
  
[avishek@tecmint ~]$ ifconfig eth0 down 
 
 

Enable Network Adapter

 
 

  
  
[avishek@tecmint ~]$ ifconfig eth0 up 
 
 

Specify the IP address to the network adapter

Set the IP address "192.168.1.12" for the network adapter eth0 ".

 
 

  
  
[avishek@tecmint ~]$ ifconfig eth0 192.168.1.12 
 
 

Change the subnet mask of the network adapter eth0:

 
 

  
  
[avishek@tecmint ~]$ ifconfig eth0 netmask 255.255.255. 
 
 

Change the broadcast address of the network adapter eth0:

 
 

  
  
[avishek@tecmint ~]$ ifconfig eth0 broadcast 192.168.1.255 
 
 

Specify the IP address, subnet mask, and broadcast address for the network adapter eth0:

 
 

  
  
[avishek@tecmint ~]$ ifconfig eth0 192.168.1.12 netmask 255.255.255.0 broadcast 192.168.1.255 
 
 

Note: If you set a wireless network card, you can use the "iwconfig" command ". for more examples and usage of ifconfig commands, read "15 useful ifconfig commands ".