Bash Shell Command to Find or Get IP address

Posted on in Categories , , , , , last updated May 28, 2011

How do I find out my Linux / UNIX system ip address, subnet and related networking information from a command prompt?

To find out IP address of Linux/UNIX/BSD/Unixish system you need to use command called ifconfig. It is used to configure the kernel-resident network interfaces. It is used at boot time to set up interfaces as necessary. After that, it is usually only needed when debugging or when system tuning is needed. If no arguments are given to ifconfig command it displays the status of the current active interfaces. It displays Ethernet IP address, Mac address, subnet mask and other information. Type /sbin/ipconfig command to display IP address:
$ /sbin/ifconfig
OR type the following command:
$ /sbin/ifconfig | less
Under Solaris and other Unixish oses you may need to type ifconfig command with -a option as follows:
$ /sbin/ifconfig -a
Sample outputs:

eth0     Link encap:Ethernet  HWaddr 00:0F:EA:91:04:07
  inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
  inet6 addr: fe80::20f:eaff:fe91:407/64 Scope:Link
  UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
  RX packets:31167 errors:0 dropped:0 overruns:0 frame:0
  TX packets:26404 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:1000
  RX bytes:38338591 (36.5 MiB)  TX bytes:3538152 (3.3 MiB)
  Interrupt:18 Base address:0xc000

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:1994 errors:0 dropped:0 overruns:0 frame:0
  TX packets:1994 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:0
  RX bytes:188041 (183.6 KiB)  TX bytes:188041 (183.6 KiB)

In above example 192.168.1.2 is IP address of eth0 Ethernet interface.

Linux ip Command

It is recommend that you use the ip command under Linux based systems. The following command will show all ip address:
# ip addr show
To see information about eth0 ip address, enter:
# ip addr show eth0
Sample outputs:

2: eth0:  mtu 1500 qdisc mq state UP qlen 1000
    link/ether b8:ac:6f:65:31:e5 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.100/24 brd 192.168.2.255 scope global eth0
    inet6 fe80::baac:6fff:fe65:31e5/64 scope link 
       valid_lft forever preferred_lft forever

For more information please see howto read UNIX/Linux system IP address in a shell script.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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53 comment

  5. hostname -i doen’t get the internet ip address:

    ?????:~ # hostname -i
    127.0.0.2

    it gives me the lo ip address.

    I want to get the internet ip address from a command.

    Regards
    Oscar

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  6. I have found this way to get my ip public address (I have two IPs in my eth0 card for NAT):
    xxxx:~ # ifconfig|sed -n “/inet addr:.*255.255.255.255/{s/.*inet addr://; s/ .*//; p}”

    Regards,
    Oscar

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  7. I’m trying OpenSuSE LiveCD 64Bits (Linux linux 2.6.25.5-1.1-default #1 SMP 2008-06-07 01:55:22 +0200 x86_64 x86_64 x86_64 GNU/Linux)

    and the previous command doesn’t work. I have different broadcast address, so I get it with the mask (that is the same):

    linux:/home/linux # ifconfig eth0 | sed -n “/inet addr:.*255.255.248.0/{s/.*inet addr://; s/.*//; p}”
    xxx.xxx.xxx.xxx
    linux:/home/linux #

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  8. Oscar, try this.

    [email protected]:~# ifconfig eth0 | grep inet | awk ‘{print $2}’ | sed ‘s/addr://’

    Where eth0 is the interface you want to know the ip address. In my case was eth0. This will retrieve the Ip Address from the specified interface. If you have ipv6 active and you only use ipv4 Address, then add a grep . to the end of the sentence.
    it would be like this:
    [email protected]:~# ifconfig eth0 | grep inet | awk ‘{print $2}’ | sed ‘s/addr://’ | grep .

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  9. I use the above to retrieve the Ip address (dynamic one) from my ISP in order to forward the HTTP petitions to the web server (behind a firewall). Hope it works for you.

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  13. that’s why i typed two lines, the first one if you don’t have inet6 active on your server, and the second one if you do have it on.

    [email protected]:~# ifconfig eth0 | grep inet | awk ‘{print $2}’ | sed ’s/addr://’ | grep . <– is not the best way to do it, but the “grep .” stuff works for that matter (at least it does for me) as i said it depends on the flavor of Linux you have and some other stuff.

    Thanks for the tip on the “space after inet” i’ll try it out..

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    1. Hi,
      in case someone still interested, i think easiest way to get local ip address is:
      hostname -I (capital i)
      this will return just the ip address with nothing else.

      To get my external ip address (without use dyndns, noip & c) i use in a script:

      wget www.whatismyip.com/automation/n09230945.asp -O /tmp/ip.txt -o /dev/null

      This will write to /tmp/ip.txt my external ip and then i upload the text file with curl
      to a directory on my web page

      #!/bin/bash
wget www.whatismyip.com/automation/n09230945.asp -O /tmp/ip.txt -o /dev/null
extip=`cat /tmp/ip.txt`
echo "$extip" > /tmp/ip.txt
hostname -I > /tmp/intip.txt
exit 0

      Bye
      Award
      ——————
      C u in /dev/null

      Reply Report comment

  15. Hi, I’m using RedHat Workstation 4 and would like to write a script to set the IP address, subnet mask and hostname of my machine. The same as Rahul.

    How can i do this?
    Thanks in advance.

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  16. A lot of the above example scripts/commands dont work corectly due to missformatting of the various Quote characters. Single quotes, double quotes and backticks are messed up.

    ` is a backtick – top left of the keyboard. Its used to go around a command thats ran.
    export FOO=`ls`
    puts the output of the ls command in the variable FOO

    single Quote ‘ and double quotes ” are used in different places to go around arguments to commands. and to keep special chaacters from gettting parsed by the shell.

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  17. oops.. Watch out for the way this thread/forum alters the matching Quote to the single and double qupte if you cut and paste the examples. ie:

    single Quotes ‘hello’

    double quotes “hello”

    back ticks `hello`

    I had to manually alter the lines after i pasted them to use proper quoteing.

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  23. I like to use the simple and concise:
    host $(hostname) | sed ‘s/.*has address //g’

    It simply returns the IP address that the rest of the world sees for your machine.

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  24. @wuhaa @Alejandro\ Smith

    Personally I prefer this version:
    $ /sbin/ifconfig eth0 | sed '/inet\ /!d;s/.*r://g;s/\ .*//g'

    Why, you may ask. Because of this:

    $ time { /sbin/ifconfig eth0|grep "inet addr:"|awk '{print $2}'|awk -F : '{print $2}' ; }
    192.168.1.8

    real 0m0.027s
    user 0m0.013s
    sys 0m0.003s

    $ time { /sbin/ifconfig eth0 | grep inet | awk '{print $2}' | sed 's/addr://' | grep . ; }
    192.168.1.8

    real 0m0.009s
    user 0m0.011s
    sys 0m0.010s

    $ time { /sbin/ifconfig eth0 | sed '/inet\ /!d;s/.*r://g;s/\ .*//g' ; }
    192.168.1.8

    real 0m0.005s
    user 0m0.005s
    sys 0m0.004s

    The fewer processes, the faster the execution.

    Reply Report comment

    2. Excellent info on that.. thanks for updating this. That’s true, fewer processes translates into a faster execution.

      Two years ago when i first posted on this faq with a “solution”, i was a new linux user, and i did not had any experience on this. I read some good information on bash scripting and came out with this solution for a problem i was having at that time.

      I didn’t care back then if it was faster than other solutions, i just needed to solve the issue.. ;-) but of course, YOU are completely right with your point of view.

      Thank you all for sharing your knowledge on this.

      God bless you all.

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    3. Similar approach, but with Awk instead of sed:

      time { ifconfig vmnet8 | awk ‘/inet addr:/ {print substr($2,6)}’ ; }

      Do some *nix implementations put a space after ‘addr:’ ? If so, this will break in those cases.

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  27. # paste this in your ~/.bashrc
    myip (){
    clear
    echo
    echo ” ip local: `hostname -I`”
    echo ” router: `route -n | awk ‘/UG/ {print $2}’`”
    echo ” external ip: `curl –connect-timeout 4 -s sputnick-area.net/ip`”
    echo
    read -sn 1 -p ” Press any key to continue…”
    clear
    }

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  31. A computer may have multiple network interfaces and therefore more than one ip-address you should try:

    /sbin/ifconfig [dev] | \
    sed -n ‘/inet [Aa]d\{1,2\}resse\{0,1\}:/ { s# *inet [Aa]d\{1,2\}resse\{0,1\}:##; s# .*##p }’

    If you omit [dev] this command will give you a list of all IP-address and should work with English and German localization.

    Have a look here (German page).

    hostname -i is unpredictable in its result and nslookup $(hostname) will give you only what DNS knows about your machine.

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  34. Just running the following

    # ip -f inet -o addr show eth0

    The result will be (on one line)

    2: eth0   inet 192.168.2.100/24 brd 192.168.2.255 scope global eth0

    Then you can apply a simple filter on it to extract the IP

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  37. I’m using cygwin on windows and a VPN. None of the above worked for me. I had to use the following command and some grep and sed commands
    route print | egrep ” 255.255.255.255.*123.123.123.123″ | sed ‘s/\s*\(.*\)255.255.255.255.*/\1/g’

    #I’ve used 123.123.123.123 as a fictional router address.

    Explanation:
    The vertical line, the pipe symbol, | , takes the output of everything on the left and feeds it to the command on the right. So the solution that works for me (the rest do not) involves essentially three commands – each of which that does something and parse things to the next step.

    route print
    the main command of many things – over many lines

    egrep ” 255.255.255.255.*123.123.123.123
    this selects a line that has the netmask at 255.255.255.255 then any characters as shown by the .* after the 255’s and then looks for my router’s address of 123.123.123.123.

    sed ‘s/\s*\(.*\)255.255.255.255.*/\1/g’
    sed command replaces/extracts text. basic use: ‘s/replace/withThis/g’ does a global search and replaces all references of replace with the string withThis.
    This sed command extracts the part of the line before the 255 part. It ignores leading spaces indicated by the \s and also anything after the 255 part shown by .* which is a shorthand for any character or number (the . part) that is found zero of more times (the * part).
    By placing part of the replace string in parentheses \(.*\) I am saying keep this part. So it’s the part after leading spaces and before the 255s. The \1 part is the replacement part of the sed command throws away all the other stuff and just keeps that part in parentheses and is displayed. This is the IP address on my machine.

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  42. How to find IP Address in Linux Operating System
    i’m using this command
    ifconfig ,/sbin/ifconfig and /sbin/ifconfig eth0 and
    ifconfig eth0 | grep inet | sed -n “s/^\s*inet addr://p” | awk ‘{ print $1 }’ and
    more command i’m using but i’m not geting a ip address pls help any one

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