Linux commands to get IP address and Hostname of a machine

Knowing the IP address and Host name of a machine are some very common requirements.

The command to get the IP address of a linux machine is
>ifconfig
eth0      Link encap:Ethernet  HWaddr 0A:90:74:4A:62:42
          inet addr:172.31.9.245  Bcast:172.31.15.255  Mask:255.255.240.0
          inet6 addr: fe80::890:74ff:fe4a:6242/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:9001  Metric:1
          RX packets:13139146 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12665241 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:10433927585 (9.7 GiB)  TX bytes:16516355937 (15.3 GiB)
          Interrupt:77

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:65536  Metric:1
          RX packets:40162017 errors:0 dropped:0 overruns:0 frame:0
          TX packets:40162017 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0

          RX bytes:6184024837 (5.7 GiB)  TX bytes:6184024837 (5.7 GiB)

The command to get the hostname of a linux machine is
>hostname
masternodemachine

Python Code Snippet to get the hostname and IP address of a machine

The following python code snippet will return the IP address of a machine

import socket

ip_address = socket.gethostbyname(socket.gethostname())

print ip_address

host_name = socket.getfqdn()

print host_name

The IP address may not be proper in all the cases. If the /etc/hosts file of the unix machine contains entries with hostname mapped to 127.0.0.1, will return 127.0.0.1 as IP address. So for ensuring proper working, it will be better to use the fully qualified hostname method.