Shell script to read file into variable

aspect_p · #1 (**permalink**) 03-19-2008

the script i am trying to write will allow my server to give itself an ip address.

So far i am up to the following but i'm stuck.

tracert -m 1 > traceroute.txt

[Outputs]
1 routername (ipaddr) 2.094 ms 1.789 ms 1.243 ms

i want to get ipaddr as a variable and use it to write the ifcfg-eth script.
How should i go about this?

jim mcnamara · #2 (**permalink**) 03-19-2008

Code:

# one way that does not use an intermediate  file
tracert -m 1 | read one two ipaddr dummy
# from the file
awk '{ print $3}' traceroute.txt | read ipaddr
# if you want to lose the ( ) around the ipaddr if you really have one
awk '{ print $3}' traceroute.txt | tr -d '('  | tr -d ')'  | read ipaddr

aspect_p · #3 (**permalink**) 03-19-2008

i am using this in the script
traceroute -m1 ipaddr |grep 10.12 |awk '{ print $3}'| tr -d '(' | tr -d ')' | read ipaddr

echo $ipaddr

the only problem now is that it wont run as a single command.

ipaddr=$ ( traceroute -m1 10.0.100.1 |grep 10.12 |awk '{ print $3}'| tr -d '(' | tr -d ')' )
tracert.sh: line 3: syntax error near unexpected token `|'
tracert.sh: line 3: `ipaddr=( traceroute -m 1 10.100.0.100 |grep 10.12 |awk '{print $3}'| tr -d '(' | tr -d ')' )'

aspect_p · #4 (**permalink**) 03-19-2008

so i got the command to work on a single line, syntax error.

What i want to do now is trim the last three digits of the ip..

I have 192.168.1.1 i'm trying to achieve 192.168.1

fpmurphy · #5 (**permalink**) 03-19-2008

Code:

$ echo "192.168.1.1" | sed 's/\([0-9]*\)\(\.[0-9]*\)\(\.[0-9]*\)\(\.[0-9]*\)/\1\2\3/'
192.168.1
$

danmero · #6 (**permalink**) 03-19-2008

Code:

 # echo "192.168.1.1" | awk -F'.' ' {IP=""; for(i=1;i<NF;i++) { IP=IP $i "." } print IP}'
192.168.1.

cfajohnson · #7 (**permalink**) 03-19-2008

Quote:

Originally Posted by aspect_p

What i want to do now is trim the last three digits of the ip..

I have 192.168.1.1 i'm trying to achieve 192.168.1

Do you want to remove the last two or the last three characters? You say three, but your example only has two removed.
Code:
ipaddr=192.168.1.1
printf "%s\n" "${ipaddr%??}"
printf "%s\n" "${ipaddr%???}"
On the other hand, if you want the last component of the dotted quad address removed:
Code:
ipaddr=192.168.1.1
printf "%s\n" "${ipaddr%.*}"

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