topic Re: awk - print range of fields in Operating System - HP-UX

awk - print range of fields

Raynald Boucher — Thu, 28 Jun 2007 10:17:04 GMT

Hello all,

I'm trying to rearrange a file where rows contain a variable number of fields.
How can I print "field 6 to end of line"?

example:
awk '{print $4 " " $2 " " $3 " " $6through$NF :'

Thanks
RayB

Re: awk - print range of fields

A. Clay Stephenson — Thu, 28 Jun 2007 10:28:10 GMT

awk '{ printf("%s %s %s ",$4,$2,$3); i = 6; while (i < (NF - 1)) { printf("%s ",$i); ++i; } printf("%s\n",$NF); }'

Re: awk - print range of fields

James R. Ferguson — Thu, 28 Jun 2007 10:32:11 GMT

Hi:

# awk '{printf "%s %s %s ",$4,$2,$3;for (i=7;i
Regards!

...JRF...

Re: awk - print range of fields

James R. Ferguson — Thu, 28 Jun 2007 10:33:26 GMT

Hi (again):

Ooops! Initialize i=6 not i=7...

Regards!

...JRF...

Re: awk - print range of fields

Sandman! — Thu, 28 Jun 2007 10:44:32 GMT

awk '{
for(i=2;i<=NF;++i) {
if (i==2)
str=$i
else if (i==3)
str=str" "$i
else if(i==4)
str=$i" "str
else if (i==5)
printf("%s ",str)
else
printf(i }
}' infile

Re: awk - print range of fields

Hein van den Heuvel — Thu, 28 Jun 2007 11:13:23 GMT

In perl you can take a slice of an array with the x .. y notation.
The elements start at 0
A little to my surprise i coudl not use [5..-1] to indicate a slice from the 6th fields thru the end.

Anyway... a perl solution:

perl -alpe '$_ = join " ",@F[3,1,2,5..@F-1]' x.tmp

-a = autosplit into array @F
-l = add newline to print
-p = print $_ before looping
-e = here comes the program

Hein.

Re: awk - print range of fields

Raynald Boucher — Thu, 28 Jun 2007 12:09:43 GMT

Thanks all,
I had never thought of the loop.

I'll have to get a book or at least a quick ref.

Thanks again.
Rayb

Re: awk - print range of fields

James R. Ferguson — Thu, 28 Jun 2007 12:16:01 GMT

Hi:

> Hein: A little to my surprise i coudl not use [5..-1] to indicate a slice from the 6th fields thru the end.

Yes, but this would work:

# perl -alpe '$_ = join " ",@F[3,1,2,-4..-1]' x.tmp

Regards!

...JRF...

Re: awk - print range of fields

Hein van den Heuvel — Thu, 28 Jun 2007 12:25:18 GMT

Ray,

Sorry for this side line

And btw...
why not just TRY the perl solution.
It's just an other language/tool.

JRF,
>> # perl -alpe '$_ = join " ",@F[3,1,2,-4..-1]' x.tmp

Yes, the -n..-m does work but the start end end of the slice would both be relative to the end. So for example for 20 fields it would return 16 .. 20, not the desired 6 .. 20.

fwiw,
Hein.

Re: awk - print range of fields

James R. Ferguson — Thu, 28 Jun 2007 12:32:00 GMT

Hi:

Hein: > Yes, the -n..-m does work but the start end end of the slice would both be relative to the end. So for example for 20 fields it would return 16 .. 20, not the desired 6 .. 20.

Yes, I now see why you chose the approach you did.

Sandman: BTW, I had not thought of using conditional operators in 'awk'. That's very nice!

Regards!

...JRF...

Re: awk - print range of fields

Raynald Boucher — Thu, 28 Jun 2007 12:47:20 GMT

Hein and James,

Sometimes I'd like to try Perl but We don't use it except in some OS scripts and noboby in my shop is proficient.
It would become a maintenance problem.

Is there a -quick- way to learn Perl?
Which manual would you recommend?

Rayb

Re: awk - print range of fields

James R. Ferguson — Thu, 28 Jun 2007 13:03:15 GMT

Hi Raynald:

I'd probably start with "Learning Perl" from the O'Reilly publishers. A compendium of links to good stuff is:

http://perlmonks.org/index.pl?node_id=284175

Like any language, the best way to really learn it is to use it.

Regards!

...JRF...

Re: awk - print range of fields

A. Clay Stephenson — Thu, 28 Jun 2007 13:59:23 GMT

The learning curve for Perl is a bit steeper than with many other scripting languages but the rewards are also greater. It's one of the very few scripting languages that are widely portable. Well-written Perl scripts will run on any flavor of UNIX, Windows, MacOS, VMS, ... without change. Unlike most scripting languages, almost anything that can be done in C can also be done in Perl.

Perhaps the worst quality of Perl is also its best quality: the ability to pack an enormous amount of processing into one line. This characteristic makes it very easy to produce Perl code that is extremely cryptic especially for beginners. It's really quite easy to write Perl in a style that is verbose and clear; it's just not done that often. I suppose that it's one of those "suffering (or at least confusion) is good for the soul" things.

Re: awk - print range of fields

Hein van den Heuvel — Thu, 28 Jun 2007 14:23:47 GMT

Btw... if the contents of field $6 van not match fields $1 - $5, then a simple awk solution could be:

$ awk '{print $4,$2,$3,substr($0,index($0,$6))}' x.tmp

If $6 is a 'short' field then you can increase its uniqueness by pre end-or post pending a knwo separator:

$ awk '{print $4,$2,$3,substr($0,index($0," " $6 " "))}' x.tmp

Cheers,
Hein.

Re: awk - print range of fields

Rodney Hills — Thu, 28 Jun 2007 16:04:44 GMT

Maybe a better tools then awk would be "cut".

cut -f 4,2,3,6- inputfile >outputfile

cut assumes tab for the delimiter, but you can override with the -d option.

HTH

Rod Hills

Re: awk - print range of fields

Dennis Handly — Thu, 28 Jun 2007 22:36:18 GMT

>Rod: Maybe a better tools then awk would be "cut".

cut(1) is usually not a better tool than awk.
It has rigorous ideas of delimiters, if you have more than one between fields.

Re: awk - print range of fields

Raynald Boucher — Fri, 29 Jun 2007 07:44:58 GMT

Thanks again, closing thread.

Re: awk - print range of fields

Raynald Boucher — Fri, 29 Jun 2007 07:48:48 GMT

Closed!