topic Re: Awk field seperator in Operating System - Linux

Awk field seperator

maliaka — Mon, 08 Jan 2007 00:43:13 GMT

Hello,

echo hello1 192.168.1.9|awk 'BEGIN { FS = "." } ; { print $1"."$2"."$3}'
hello1 192.168.1

I only need to pring the first three octats from the second field and delete the first field (hello1).

The echo string is an output from a loop.

Thanks

Re: Awk field seperator

Steven E. Protter — Mon, 08 Jan 2007 01:01:07 GMT

Shalom,

I have some non awk code that I was given on ITRC that does this job.

IP=`expr "${LINE}" : ".*[^0-9]$[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*$.*"`

The expression above grabs the first three octets of an ip address.

It doesn't use awk though.

SEP

Re: Awk field seperator

Steven E. Protter — Mon, 08 Jan 2007 01:11:57 GMT

Hey, there is some awk code after all.

OCT1=`echo $IP | awk -F. '{print $1}'`
OCT2=`echo $IP | awk -F. '{print $2}'`
OCT3=`echo $IP | awk -F. '{print $3}'`
IPB=`echo $OCT1.$OCT2.$OCT3`

After what I posted.

Sorry for splitting the post, it was not intentional. Please provide me the slapping I so richly deserve in the point assignment phase(e.g. don't assign to both posts).

Thanks.

SEP

Re: Awk field seperator

maliaka — Mon, 08 Jan 2007 01:20:50 GMT

I know that I can use echo strings to split the fields as much as I know there is away to do all of that in one line.

10 points for the right answer.

Re: Awk field seperator

albanese — Mon, 08 Jan 2007 04:34:32 GMT

Try This one

echo hello1 192.168.1.9 | awk 'BEGIN { FS = "." } ; { print substr($1,8,11)"."$2"."$3}'

result

192.168.1

Re: Awk field seperator

albanese — Mon, 08 Jan 2007 04:49:40 GMT

It gives the same output the previous one has an extra character. but doest make a difference.

echo hello1 192.168.1.9 | awk 'BEGIN { FS = "." } ; { print substr($1,8,10)"."$2"."$3}'

Re: Awk field seperator

Yarek — Mon, 08 Jan 2007 05:24:13 GMT

pls try:

echo hello1 192.168.1.9 | awk '{print $2}' |
awk -F"." '{print $1"."$2"."$3}'

output should be:

192.168.1

rgds

Re: Awk field seperator

Peter Godron — Mon, 08 Jan 2007 06:52:54 GMT

echo hello1 192.168.1.9 | cut -d' ' -f 2 | cut -d'.' -f1-3

Re: Awk field seperator

Peter Nikitka — Mon, 08 Jan 2007 07:11:33 GMT

Hi,

because the first field is 'hello1 192' in respect to the filed delimiter '.', you get what awk was told to do.

echo hello1 192.168.1.9|awk '{split($2,a,"."); printf("%s.%s.%s\n" a[1],a[2],a[3])}'

mfG Peter

Re: Awk field seperator

James R. Ferguson — Mon, 08 Jan 2007 07:56:34 GMT

HI:

# echo hello1 192.168.1.9|awk -F"[ .]" 'BEGIN{OFS="."};{print $2,$3,$4>

192.168.1

Note that the input field separator is a character class consisting of a space (blank) or a dot (".").

Regards!

...JRF...

Re: Awk field seperator

spex — Mon, 08 Jan 2007 08:01:24 GMT

Hi,

Change awk's field separator regex to recognize both . and space.

$ echo hello1 192.168.1.9 | awk -F'[. ]' '{print $2"."$3"."$4}'
192.168.1

PCS

Re: Awk field seperator

Geoff Wild — Mon, 08 Jan 2007 09:50:14 GMT

Very nice spex - definately a 10 in my books!

I would have just piped through 2 awk statements - forgot about regex.

IE:

echo hello1 192.168.1.9 | awk '{print $2}' | awk -F. '{print $1"."$2"."$3}'

Rgds...Geoff

Re: Awk field seperator

James R. Ferguson — Mon, 08 Jan 2007 10:20:22 GMT

Hi (again):

Well, it appears that Spex and I agree on the solution :-))

Regards!

...JRF...

Re: Awk field seperator

Hein van den Heuvel — Mon, 08 Jan 2007 12:49:38 GMT

I would use a -F [ .] solution.
But you could take the default whitespace field seperator and substitute a period followed by numbers at the end of $2 with nothing:

awk '{sub (/.[0-9]+$/,"",$2); print $2}'

Or you can 'match' the first 3 groups of numbers seperated by a period and print that.
That would allow this to work in free formatted text, not just on 'the second field'.

awk '{match($0,/[0-9]+\.[0-9]+\.[0-9]+/); print substr($0,RSTART,RLENGTH)}'

Enjoy,
Hein.

Re: Awk field seperator

albanese — Tue, 09 Jan 2007 05:24:43 GMT

I prefer James R. Ferguson Solution.. Cheers.

Re: Awk field seperator

maliaka — Tue, 09 Jan 2007 20:20:44 GMT

Thanks a lot for the great solutions.

Have you guys tried to double quote the echo string?
By default the -F,FS and OFS are a space character so if you put the echo string in double quote, it preserves the white space and therefore mess it up if add spaces. Try it.

Hein has provided the best solution so far!!!

Open for debate.

Re: Awk field seperator

Peter Nikitka — Wed, 10 Jan 2007 04:58:00 GMT

Hi,

the result of
echo a b | prog
echo 'a b' | prog
echo "a b" | prog

or
prog $(echo a b)
...

will be the same. In the view of the 'echo' command, it's different - in the first case it sees two parameters, in the other one parameter. But the result is the same: 'echo' will send the two parameters to its output, seperated by a space - which is exactly the same in case 2 or 3, where the space is taken from the original input of the single parameter.

Different will be a scenario like this:
echo ab
echo 'ab'

Only in the first case the result would NOT contain a TAB, but a space!

mfG Peter

Re: Awk field seperator

maliaka — Wed, 10 Jan 2007 21:58:21 GMT

I have another question?

I would like to get only the first line from the output? (whatever the output might be).

awk '/'hell'/ && !/awk/ {print
$3}' /tmp/target.txt
HH
HH
HH
HH

Re: Awk field seperator

Denver Osborn — Wed, 10 Jan 2007 22:19:27 GMT

to get the first line of the output, no matter what it may be... just pipe it to head -1.

awk '/'hell'/ && !/awk/ {print $2}' /tmp/target.txt |head -1

-denver

Re: Awk field seperator

Denver Osborn — Wed, 10 Jan 2007 22:32:23 GMT

also w/ awk using your syntax modified...

awk 'NR>1{exit}/'hell'/ && !/awk/ {print $3}' /tmp/target.txt

-denver