Awk ignoring variable

Shell Programming and Scripting
1

If anyone knows why $cc is ignored in the following awk.
When I use a value it works ok.
cc=`grep -a "ControlID" in.file | cut -c 375-378`

$cc is equal to "XXXX"

does not work:
cat in.file|awk -v cnt=0 -v replace=" " '/$cc/{if (cnt=="0"){sub(/$cc/,replace)};cnt++} {print}' > out.file

works:
cat in.file|awk -v cnt=0 -v replace=" " '/XXXX/{if (cnt=="0"){sub(/XXXX/,replace)};cnt++} {print}' > out.file

2

Hi.

You're using a shell variable inside awk.

awk -v cnt=0 -v replace="    " '/'$cc'/ {if (cnt=="0"){sub(/$cc/,replace)};cnt++} {print}' in.file > out.file

or

awk -v cnt=0 -v cc=$cc -v replace="    " '$0 ~ cc {if (cnt=="0"){sub(/$cc/,replace)};cnt++} {print}' in.file > out.file
3

You've blocked the shell from expanding $cc with the single quotes:

cat in.file|awk -v cnt=0 -v replace="NEWSTUFF" "/$cc/{if (cnt=="0"){sub(/$cc/,replace)};cnt++} {print}" > out.file

Of course, now you must be careful of any currency signs ($) in your awk(1) script.

4

Thank Guys! I'm doing some testing. Looks like it works for the first occurance in the file when the cnt=0, but when I change the... if cnt=="1" then the second does not get change... I'll do more testing.

5

It's not a great idea to use double quotes to start and end an awk script:

$ echo something | awk "{print $NF}"   
something
 
$ echo something | awk "{ if ($1 == "something") A=$1 }"
awk: { if ( == something) A= }
awk:        ^ syntax error
 
$ echo something | awk "{print "Here is " $NF}" 
awk: cmd. line:1: {print Here
awk: cmd. line:1:            ^ unexpected newline or end of string
 
$ echo something | awk "{print 'Here is ' $NF}"
awk: {print 'Here is ' }
awk:        ^ invalid char ''' in expression
 
$ echo something | awk "{print \"Here is \" $NF}"
Here is

Use single quotes and declare the shell variable to awk either as

awk -v cc=$cc '...' file1 file2 ... etc.
or
awk '...' cc=$cc file1 dd=$dd file2 ... etc.

depending on your preference and whether you have a BEGIN clause or not.