[SOLVED] ip address of machine using bash script

shashv2 · 07-22-2010, 06:27 AM

I want to get only the IP address of the machine and store it in a variable. I have tried following commands and I get an error

IP =`ifconfig eth0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}'`
IP =$(ifconfig eth0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}')

Error is -

/filename.sh: line 2: IP: command not found

Any help will be appreciated.

Thanks,

Nylex · 07-22-2010, 06:36 AM

The spaces in "IP = ..." could be the problem. When you initialise variables in Bash, you must not use spaces.

angel115 · 07-22-2010, 06:49 AM

Or here is on other solution:

Code:

$ ifconfig eth0 |sed -n "/inet addr/p"| sed -e "s/\s*Bcast.*$//"|sed -e "s/^.*://"
192.168.123.102

angel115 · 07-22-2010, 06:51 AM

Sorry forget my previous post, I miss read the question, Nylex is correct.

grail · 07-22-2010, 08:47 AM

Nylex has provided the correct answer to the assignment, but let us be concise with our commands. There is no need to use several when one is plenty:

Code:

#sed
ifconfig eth0 | sed -n -r '/inet addr/s/^[^:]*:([^ ]+) .*/\1/p'

#awk
ifconfig eth0 | awk '/inet addr/{print gensub(/addr:/,"","1",$2)}'

b0uncer · 07-22-2010, 10:04 AM

I'll add some more hay to the stack. Altough this is not as short nor easy (and probably less efficient too) as the sed/awk solutions above, it'll demonstrate more ways to get around this problem, especially if one wishes to use something else than bash.

Code:

perl -e '$t=qx/ifconfig eth0/;if($t=~/\s*inet addr:([\d.]+)/){$ip=$1} print "$ip\n";'

Have a nice day

ghostdog74 · 07-22-2010, 08:52 PM

Code:

$ var=$(ifconfig wlan0)
$ var=${var##*inet addr:}
$ echo ${var%% *}

Telengard · 07-22-2010, 09:00 PM

OP's question has already been answered, but just for fun ... this works for any host on the LAN if you have nmbd running:

Code:

ip=$( nmblookup NETBIOSNAME | grep -v query | awk '{ print $1 }' )

ghostdog74 · 07-22-2010, 09:06 PM

Quote:

Originally Posted by Telengard

OP's question has already been answered, but just for fun ... this works for any host on the LAN if you have nmbd running:

Code:

ip=$( nmblookup NETBIOSNAME | grep -v query | awk '{ print $1 }' )

grep and awk share the same functions.

Code:

ip=$( nmblookup NETBIOSNAME |awk '!/query/{ print $1 }' )

Telengard · 07-22-2010, 10:45 PM

Quote:

Originally Posted by ghostdog74

Code:

ip=$( nmblookup NETBIOSNAME |awk '!/query/{ print $1 }' )

Nice simplification!