topic Re: use variable in awk.. in Operating System - HP-UX

use variable in awk..

amonamon — Wed, 09 Aug 2006 03:53:38 GMT

Hello I have part of my program that uses awk..and calculate value...
so I get $w variable with one value..

then in the other part of script I want to use that value in other nawk...

basiclly

other part would be...
...
...
..

q=`cat file20060808 | wc -l`
echo $q

nawk -F"|" -v x=20060808 -v w=$q'
{u=u+1; l=l+$77}
($77 != 0)&&($123 == 1)&&($124 == 0) { a=a+1; s=s+$77}
END { print x"|"u"|"l"|"q"|"s } ' fileA >> final

but this does not pass value of echo $q to my nawk..

do I miss something?

thanks

Re: use variable in awk..

Chan 007 — Wed, 09 Aug 2006 04:41:09 GMT

Hi,

Why is this line, with only one "'"?

nawk -F"|" -v x=20060808 -v w=$q'

Chan

Re: use variable in awk..

amonamon — Wed, 09 Aug 2006 05:28:18 GMT

I was just courious how to pass variable from previous operation to this nawk..so that nawk can print it in its print function...

Re: use variable in awk..

Chan 007 — Wed, 09 Aug 2006 05:43:26 GMT

Hi,

try passing like w=$(echo $q)

Chan

Re: use variable in awk..

amonamon — Wed, 09 Aug 2006 05:51:51 GMT

chan...perfecto...that worked...;)

Re: use variable in awk..

Peter Nikitka — Wed, 09 Aug 2006 09:41:14 GMT

Hi,

using 'nawk' tells me that you probably are working under Solaris...

Nevertheless this should work, since the spaces are stripped from the content of $q:

x=file20060808
q=`wc -l <$x`
echo "'$q'" # blanks contained
q=`echo $q` # no blanks contained
q=`wc -l <$x | tr -d ' '`
echo "'$q'" # no blanks contained

nawk -F'|' -v x=$x -v w=$q '...

mfG Peter

Re: use variable in awk..

Hein van den Heuvel — Wed, 09 Aug 2006 10:33:00 GMT

amonamon,

>>> q=`cat file20060808 | wc -l`

Why create a process, activate 'cat' and pipe all the data to wc when wc is perfectly happy to read the file itself?

>>> then in the other part of script I want to use that value in other nawk...

The problem has been solved in prior replies, but I'd like you to consider just doing all the work in AWK.

Something like (untested...)

nawk -F"|" -v x=20060808 '
BEGIN {file = "file" x; while (getline < file ) {w++}}
{....

btw... in your question yo pick up $q, try to assign to awk variable 'w' but then appear to use 'q' in the END for the awk script. Did you not intent to use 'w' in the print, or just use q as the variable for awk as well?

fwiw,
Hein.

Re: use variable in awk..

Bill Hassell — Wed, 09 Aug 2006 11:27:25 GMT

Another technique to pass shell variables to awk/nawk is to single quote the special awk symbols, then insert the variable in the appropriate location:

SEARCHSTRING="somePattern"
awk '/'"$SEARCHSTRING"'/ {print $2}' /mypath/myfile

or

MYFIELD=5
awk '{ print $'$MYFIELD'}'

Just escape the characters needed by awk and insert the variable's value as needed. It's a little simpler than using awk variables on the command line. But if you need the awk variables inside a separate script (not in the command line or in a here document), you can use the previous examples.

Re: use variable in awk..

James R. Ferguson — Wed, 09 Aug 2006 12:19:30 GMT

Hi:

Most modern versions of 'awk' support the '-v' option for passing variables. Older versions insist the the external assignment is made as part of the argument list passed. Compare:

# awk -v VAR="world" 'BEGIN{print "hello",VAR}' /dev/null

# awk -v VAR="world" 'END{print "hello",VAR}' /dev/null

# awk 'BEGIN{print "hello",VAR}' VAR="world" /dev/null

# awk 'END{print "hello",VAR}' VAR="world" /dev/null

Note particularly the diffence in output in the third form. The advanage to the '-v arg=value' form is that variable assignment occurs even before the 'BEGIN' rules are executed.

Regards!

...JRF...