How to pass a variable to Awk ?

Shell Programming and Scripting
1

I am trying to pass 2 shell variable's ("START" and "END") define earlier in the script to this awk statement, but i can't seem to pass it on. PLs help.

set START = xxxx
set END = yyyy

set selected_file = `awk '/$START/,/$END/' filename`

2

supposedly, the -v switch is used to passed in shell variables
please check your man page.

3

try
shellvar1=xxx
shellvar2=zzz

whatever shell stuff | awk '
{
awkvar1="'$shellvar1'" # This is shell var 1
awkvar2="'$shellvar2'" # This is shell var 2

do your awk thing

}'

Note the double and single quotes....

4

Try This

Gaurav

5

awk -v ST=$START -v EN=$END '/ST/,/EN/' filename ==> can't work , but thanks anyway

i found the solution ->
set selected_file = `awk '/'"$START"'/,/'"$END"'/' filename`

6

why its not working? can u paste the output of this command.

also note that if u are on Solaris use nawk instead of awk

7

it doesn't work because 'ST' and 'EN' are taken as literal strings and not as 'variables':

awk -v ST=$START -v EN=$END '$0 ~ ST , $0 ~ EN' filename
8

Hi vgersh,

Thanks, your's works. Can you explain to me what does your syntax '$0 ~ ST , $0 ~ EN' mean ?

9

reminds me of '/ST/,/EN/', doesn't it?

10

Hi All,

I need to pass variable to awk. But the variable is in shell array format.
How do i pass it thro' ?

my awk script is below where $LOT[$num] is the shell array variable.

$2 ~ "'"$LOT['"$num"']"'" && $3 ~ "SMR1" {gds1 = $6;}
$2 ~ "'"$LOT['"$num"']"'" && $3 ~ "SMR2" {gds2 = $6;}
$2 ~ "'"$LOT['"$num"']"'" && $3 ~ "SMRG" {gdsG = $6;}

END{printf ("%5s\n",gds1 + gds2 + gdsG );}
11 
awk -v num=$num ' {
$2 ~ "'"${LOT[num]}"'" && $3 ~ "SMR1" {gds1 = $6;}
$2 ~ "'"${LOT[num]}"'" && $3 ~ "SMR2" {gds2 = $6;}
$2 ~ "'"${LOT[num]}"'" && $3 ~ "SMRG" {gdsG = $6;}
}
END{printf ("%5s\n",gds1 + gds2 + gdsG );} ' file
12

hi Anbu,

It didn;t seem to work.
Error is "no match".

I am using solaris and using csh
I used "nawk -v num=$num -f awking2 filename" where awking2 is my awk file.

Can you help ?

13

Insert the awk script directly in your shell script instead of awk file

14

Hi anbu,

I still can't get it to work. Error msg is "Unmatched ' "

15

Can you show the trace of your script?

16 
set num = 1

while ( $num <= $#table )

set check_file = `cat $script/test.csv|grep $LOT[$num]|grep $aa[$num]| awk '{print("already_appended")}'`
echo "$table[$num] is undercheck now."

if ( $check_file != "already_appended" ) then
nawk -f $script_dir/summary/gather_awk $table[$num] >> $script_dir/test.csv
echo "$table[$num] will be appended"

#nawk -v num=$num -f awking2 *csv
nawk -v num=$num ' {
$2 ~ "'"${LOT[num]}"'" && $3 ~ "g1" {gds1 = $6;}
$2 ~ "'"${LOT[num]}"'" && $3 ~ "g2" {gds2 = $6;}
$2 ~ "'"${LOT[num]}"'" && $3 ~ "gG" {gdsG = $6;}
}
END{printf ("%5s\n",gds1 + gds2 + gdsG );} ' *csv
set total = `cat $script/test.csv|grep $LOT[$num]|grep $suffix[$num]|awk '{print($6)}'`

echo ""


else

echo "$table[$num] will NOT be appended"

endif

set num = `echo $num + 1|bc`

end
17

I am not familiar with the csh syntax.In ksh we use following command to get the trace.

set -vx
18

Csh don;t use that, i believe.

Anbu , is there any other ways ?

19

check this link for unmatched error
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=996187&admit=-682735245\+1171606612762\+28353475

check this link for trace in C shell

20

I tired to use the #/bin/csh -vx and the code paused at the nawk line.
nawk -v num=$num '{
Unmatched '

Is there some thing wrong with the syntax of "'"${LOT[num]}"'" ?