Assign o/p of awk to a variable

Shell Programming and Scripting
1

:confused: Hi UNIX gurus,

I am facing a typical problem while assigining while assigining output of awk to a variable.

I have a fixed length file say myinputfile.txt

When I allow the value/output of an awk to be redirected to a file, it works fine. i.e.
awk "/^.{232}$acctNum/ { printf(\"%s;Y;Account#\n\",substr(\$0,241,1)) ; exit} " myinputfile.txt >> mylogfile.txt

However, when I try to assign the the value of same to a variable, and then echo the variable, it displays blank.i.e.
myvariable=`awk "/^.{232}$acctNum/ { printf(\"%s;Y;Account#\n\",substr(\$0,241,1)) ; exit} " myinputfile.txt`

Can somebody please help. :confused:

2

Is this $acctNum a variable or pattern?

3

It is a variable.

4

Are you sure that you are getting output from awk command?
can you show your input file?

5

Only awk is working fine. However, while assigning the same to variable, it is not working.

My Sample Inputfile is as shown below:

MyAdd1 MyAdd2 MyAdd3 MyAdd4 MyAdd5 Sachin Tendulkar 222 222-2222 11111111111111A0000111122223333XYX
YourAdd1 YourAdd2 YourAdd3 YourAdd4 YourAdd5 Rahul Dravid 111 121-5555 22222222222222B0123456789123456XYX

(In above example, spaces are getting truncated in this forum)
Basically, position 233-240 denotes account number. Also, by substring, I am trying to extract 241 character.

6

Add another backslash before $0

myvariable=`awk "/^.{232}$acctNum/ { printf(\"%s;Y;Account#\n\",substr(\\$0,241,1)) ; exit} " myinputfile.txt`
7

Hey Thank you anbu :slight_smile:

But I have two question? :confused:
Can you please clearify them.

  1. I thought only single slash is required for escaping, then whats the meaning of double slash.

  2. Also why doesnt the following one work:
    myvariable=`awk '/^.{232}$acctNum/ { printf("%s;Y;Account",substr($0,241,1)) ; exit} ' myinputfile.txt`
    In this case we dont even need escaping. :confused:

8 
YYYN939@CANPC-003249 ~
$ x=`awk "{ print \$0 }" f`
x=`awk "{ print \$0 }" f`
awk "{ print $0 }" f
++ awk '{ print bash }' f
+ x=

YYYN939@CANPC-003249 ~
$ x=`awk "{ print \\$0 }" f`
x=`awk "{ print \\$0 }" f`
awk "{ print \$0 }" f
++ awk '{ print $0 }' f
+ x='Hi
How are you'

YYYN939@CANPC-003249 ~
$ x=$(awk "{ print \$0 }" f)
x=$(awk "{ print \$0 }" f)
awk "{ print \$0 }" f
++ awk '{ print $0 }' f
+ x='Hi
How are you'

This wont work because variable substitution wont occur inside single quotes. So this variable $acctNum wont expand.
You can use try this

awk -v no var=$acctNum ' $0 ~ "^.{232}"var { ... } ' file

or

awk '/^.{232}'"$acctNum"'/ { ... } ' file
9

I have a similar problem by assigning a value of a command to a variable. In this case, with:
Get list of Network interfaces: /usr/sbin/networksetup -listnetworkserviceorder
Get specifically the one that contains the word "Ethernet": awk -F'\\) ' '/\Ethernet/ {print $2}'`

Assign the whole string to a variable called: "networkInterface": networkInterface= "`/usr/sbin/networksetup -listnetworkserviceorder | awk -F'\\) ' '/\Ethernet/ {print $2}'`"

Any ideas? I'm really stuck in here.:frowning: