Shell Programming and Scripting

Im trying to brush up with my awk knowledge and update some old scripts to be a little more compact...

What I would like to know how to do is the following:

Code:

hostname,10.10.10.1

I have the above csv (with many more fields of course) how can I write a single line to pull field 2 from the csv, and then split up the ip address (which is the gateway) with field seperator of .?

Currently I use two variables to do this... I'd like to be able to use one.

Code:

GWIP=`awk -v host=$1 -F, '{if ( $1 == host ) print $2}' input.csv`
IP_ADD=`echo $GWIP | awk -F. '{print $1"."$2"."$3}'`

So, How can I do the above in one awk line?

If your awk supports if, you can use:

Code:

awk -F"[,.]" '/^host/ { print $2 "." $3 "." $4 }'

Or with sed, regardless:

Code:

sed -n "/^host/s/.*,\(.*\)\..*/\1/p"

im using gawk, so the awk command you gave works, except I just snipped out only 2 of the fileds in the example i gave... I rather not go that route.

The sed command probably wont work either since there are other fields that have .'s in them

I think I can do what I need to do with sub or gsub within awk... but I cant seem to get the syntax right.

How about...

Code:

IPA=($(awk -v host=$1 -F ',' '{if ( $1 == host ) {gsub(/\./, " ", $2); print $2}}' input.csv))
echo ${IPA[*]}

IPA is array of IP fields. Change '*' to 0 through 3 for individual fields.

I wonder if AWK would run faster with a line pattern match rather than an IF statement but it would require careful substitution. Have to use double quotes to get shell $1 into AWK and then escape AWK double quotes and dollar signs.

Code:

GWIP=($(awk -F ',' "/^$1,/{gsub(/\./, \" \", \$2); print \$2}" input.csv))
echo ${GWIP[*]}

Scottn's code gives results identical to the script you provided:

Code:

10.10.10

So could you clarify what you are looking for?

I was able to use the first suggestion! I appreciate the help.

Scrutinizer,
In the example csv file I gave... I only listed the two fields I was working with, the actual csv has 22 fields; and some of the host names are used in other fields in other records. So I have to use the if statement or ill get duplicate entries... its also not the first field so even with the "^" ill still get duplicates.

OK, it is important to be specific with your problem statement, otherwise people do unnecessary work. As it turns out, the input file description did not correspond sufficiently with the actual requirements.