I want to make big script on my Debian 7.3 ( something like translated and much more new user friendly enviroment ). I have a problem. I want to use only some of the informations that commands give me. For example my ifconfig looks like:
eth0 Link encap:Ethernet HWaddr 08:00:27:a3:e3:b0
inet addr:192.168.1.103 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fea3:e3b0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1904 errors:0 dropped:0 overruns:0 frame:0
TX packets:2002 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1309425 (1.2 MiB) T
I want to display only the IP address in line: echo "Your IP address is: (IP_ADDRESS )". Is there any command that allow me to do such a thing, to search in stream for informations I want to get?. I know about grep and sed but I am not really good with them.
Edit: Firstly to say thank you for helping me with this problem, now I know much more. Secondly to say project is in progress. If anyone would be interested in it just pm me.
To just get your IP address:
echo `ifconfig eth0 2>/dev/null|awk '/inet addr:/ {print $2}'|sed 's/addr://'`
This will give you the IP address of eth0.
Edit: Due to name changes of interfaces in recent versions of Ubuntu, this doesn't work anymore. Instead, you could just use this:
hostname --all-ip-addresses or hostname -I, which does the same thing (gives you ALL IP addresses of the host).
ip -4 addr show eth0 | grep -oP "(?<=inet ).*(?=/)"
ip route get 8.8.8.8| grep src| sed 's/.*src \(.* \)/\1/g'|cut -f1 -d ' '
If the goal is to find the IP address connected in direction of internet, then this should be a good solution.
UPDATE!!! With new version of linux you get more information on the line:
ip route get 8.8.8.8
8.8.8.8 via 10.36.15.1 dev ens160 src 10.36.15.150 uid 1002
cache
so to get IP you need to find the IP after src
ip route get 8.8.8.8 | awk -F"src " 'NR==1{split($2,a," ");print a[1]}'
10.36.15.150
and if you like the interface name
ip route get 8.8.8.8 | awk -F"dev " 'NR==1{split($2,a," ");print a[1]}'
ens192
ip route does not open any connection out, it just shows the route needed to get to 8.8.8.8. 8.8.8.8 is Google's DNS.
If you like to store this into a variable, do:
my_ip=$(ip route get 8.8.8.8 | awk -F"src " 'NR==1{split($2,a," ");print a[1]}')
my_interface=$(ip route get 8.8.8.8 | awk -F"dev " 'NR==1{split($2,a," ");print a[1]}')
Why other solution may fail:
ifconfig eth0
Hostname -I
If You want to use only sed to extract IP address:
ifconfig eth0 2>/dev/null sed -n 's/.*[[:space:]]\([[:digit:]][[:digit:]]*\.[[:digit:]][[:digit:]]*\.[[:digit:]][[:digit:]]*\.[[:digit:]][[:digit:]]*\).*/\1/p'
May be not for all cases (especially if you have several NIC's), this will help:
hostname -I | awk '{ print $1 }'
awk '/inet addr:/{gsub(/^.{5}/,"",$2); print $2}' file
192.168.1.103
A slight modification to one of the previous ip route ... solutions, which eliminates the need for a grep:
ip route get 8.8.8.8 | sed -n 's|^.*src \(.*\)$|\1|gp'
In my opinion the simplest and most elegant way to achieve what you need is this:
ip route get 8.8.8.8 | tr -s ' ' | cut -d' ' -f7
ip route get [host] - gives you the gateway used to reach a remote host e.g.:
8.8.8.8 via 192.168.0.1 dev enp0s3 src 192.168.0.109
tr -s ' ' - removes any extra spaces, now you have uniformity e.g.:
8.8.8.8 via 192.168.0.1 dev enp0s3 src 192.168.0.109
cut -d' ' -f7 - truncates the string into ' 'space separated fields, then selects the field #7 from it e.g.:
192.168.0.109
If you want to get a space separated list of your IPs, you can use the hostname command with the --all-ip-addresses (short -I) flag
hostname -I
as described here: Putting IP Address into bash variable. Is there a better way?
Take your pick:
$ cat file
eth0 Link encap:Ethernet HWaddr 08:00:27:a3:e3:b0
inet addr:192.168.1.103 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fea3:e3b0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1904 errors:0 dropped:0 overruns:0 frame:0
TX packets:2002 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1309425 (1.2 MiB) T
$ awk 'sub(/inet addr:/,""){print $1}' file
192.168.1.103
$ awk -F'[ :]+' '/inet addr/{print $4}' file
192.168.1.103
Just a note, since I just spent some time trouble-shooting a botched upgrade on a server.
Turned out, that (years ago) I had implemented a test to see if dynamically added interfaces (e.g. eth0:1) were present, and if so, I would bind certain proggis to the 'main' IP on eth0. Basically it was a variation on the 'ifconfig|grep...|sed... ' solution (plus checking for 'eth0:' presence).
The upgrade brought new net-tools, and with it the output has changed slightly:
old ifconfig:
eth0 Link encap:Ethernet HWaddr 42:01:0A:F0:B0:1D
inet addr:10.240.176.29 Bcast:10.240.176.29 Mask:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1460 Metric:1
...<SNIP>
whereas the new version will display this:
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1460
inet 10.240.212.165 netmask 255.255.255.255 broadcast 10.240.212.165
...<SNIP>
rendering the hunt for 'eth0:' as well as 'inet addr:' search busted (never mind interfaces called 'em0','br0' or 'wlan0'...). Sure you could check for 'inet ' (or 'inet6'), and make the addr: part optional, but looking closer, you'll see that more or less everything has changed, 'Mask' is now 'netmask',...
The 'ip route ...' suggestion's pretty nifty - so maybe:
_MyIP="$( ip route get 8.8.8.8 | awk 'NR==1 {print $NF}' )"
if [ "A$_MyIP" == "A" ]
then
_MyIPs="$( hostname -I )"
for _MyIP in "$_MyIPs"
do
echo "Found IP: \"$_MyIP\""
done
else
echo "Found IP: $_MyIP"
fi
Well, something of that sort anyway. Since all proposed solutions seem to have circumstances where they fail, check for possible edge cases - no eth, multiple eth's & lo's, when would 'hostname -i' fail,... and then decide on best solution, check it worked, otherwise 2nd best.
Cheers 'n' beers!
/sbin/ifconfig eth0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}'
Source: Stackoverflow.com