topic Re: script variables within awk in Operating System - HP-UX

script variables within awk

Sylvain CROUET — Mon, 22 Dec 2003 11:23:05 GMT

Hi!

I use variables within a script and I would like to use them within an awk command without the -v option.
For example:
THRESHOLD1=90
THRESHOLD2=95
bdf | awk '{print $1, ":$THRESHOLD1:$THRESHOLD2"}' > FILE

I know this would work:
bdf | awk -v thr1=$THRESHOLD1 -v thr2=$THRESHOLD2 '{print $1, ":thr1:thr2"}' > FILE

but I am looking for something... smarter.

Can someone help me?

Re: script variables within awk

ian Dennison — Mon, 22 Dec 2003 11:32:43 GMT

perform a "print" of the line "bdf | awk '{print $1, $THRESHOLD1:$THRESHOLD2"}' " and redirect to a temporary file. Then run that file using the 'sh' command.

This is helpful if the number of variables to ber passed is not known

Alternatively you can string these variables together to pass only 1 variable to the awk statement!

Share and Enjoy! Ian

Re: script variables within awk

Sylvain CROUET — Mon, 22 Dec 2003 11:34:39 GMT

I prefer the second solution.

Re: script variables within awk

Rodney Hills — Mon, 22 Dec 2003 11:42:31 GMT

Using "-v" is the standard awk mechanism for passing variables. You could use "perl" instead.

bdf | perl -nae 'print "$F[0]:$ENV{THRESHOLD1}:$ENV{THRESHOLD2}' >FILE

HTH

-- Rod Hills

Re: script variables within awk

curt larson_1 — Mon, 22 Dec 2003 11:45:12 GMT

depends on which version of awk your running,
if it is a newer version, such as on an 11i system, you can use the ENVIRON array to access the values

export THRESHOLD1=90
export THRESHOLD2=95
bdf | awk '{print "$1, :ENVIRON[THRESHOLD1]:ENVIRON[THRESHOLD2]";}' > FILE

and of course you can also pass values to awk using the command line via argc and argv somewhat like a c program

Re: script variables within awk

Sylvain CROUET — Mon, 22 Dec 2003 11:48:17 GMT

Interesting ideas but I do not have very recent servers and perl is not installed on all machines.

Re: script variables within awk

curt larson_1 — Mon, 22 Dec 2003 11:49:18 GMT

you'll need double qoutes around the variable name

ENVIRON["THRESHOLD1"]

and you don't have to export the variables;
export THRESHOLD1=90

Re: script variables within awk

Michael Schulte zur Sur — Mon, 22 Dec 2003 15:47:55 GMT

Hi,

believe Curt, environ is what you need to evaluate envoronment variables from within awk. See man awk.

greetings,

Michael

Re: script variables within awk

Sylvain CROUET — Tue, 23 Dec 2003 04:13:03 GMT

Yes, ENVIRON seems to be what I need, but my Solaris machines do not seem to implement a correct version of awk as there is no ENVIRON variable within the awk manual page and it does not work as it does under HP-UX.

Re: script variables within awk

Dietmar Konermann — Tue, 23 Dec 2003 04:19:28 GMT

On Solaris you may try /usr/xpg4/bin/awk instead.

Re: script variables within awk

Michael Schulte zur Sur — Tue, 23 Dec 2003 04:31:28 GMT

Hi,

can you post an example and why it does not work, i mean any error messages?

greetings,

Michael

Re: script variables within awk

Jean-Luc Oudart — Tue, 23 Dec 2003 05:00:44 GMT

awk -v would be the solution , I don;t know why you don't want to use it !

Nevertheless, you can run something like :
(echo 90 && echo 95 && bdf) |
awk 'BEGIN{getline; th1=$0; getline; th2=$0; }
{print $1,th1,th2;}'

Regards,
Jean-Luc

Re: script variables within awk

Michael Schulte zur Sur — Tue, 23 Dec 2003 05:23:55 GMT

Hi,

there is an alternativ to environ. Store the values of the environment variables into a file and then read them ony by one.

getline < extvarfile; var1=$0;
getline < extvarfile; var2=$0;

greetings

Michael

Re: script variables within awk

Sylvain CROUET — Tue, 23 Dec 2003 06:03:04 GMT

I finally used Ian's solution; but Curt's solution, with the precision brougth by Dietmar, works fine too.

Re: script variables within awk

James Lynch — Tue, 23 Dec 2003 08:48:44 GMT

It's all in the quoting. You could do this:

THRESHOLD1=90
THRESHOLD2=95
bdf | awk "{print \$1, \":$THRESHOLD1:$THRESHOLD2\"}" > FILE

JL

Re: script variables within awk

Rory R Hammond — Tue, 23 Dec 2003 11:34:42 GMT

I am going to show two other suggestions that didn't show up in the thread.

THRESHOLD1=90
THRESHOLD2=95
bdf | awk '{print $1, ":"THRESHOLD1":"THRESHOLD2}' THRESHOLD1=$THRESHOLD1 THRESHOLD2=$THRESHOLD2 > FILE

or

bdf | awk '{print $1, ":"THRESHOLD1":"THRESHOLD2}' THRESHOLD1=90 THRESHOLD2=95 > FILE

Rory