LinuxQuestions.org - Help needed with awk

- Linux - General (https://www.linuxquestions.org/questions/linux-general-1/)

- - Help needed with awk (https://www.linuxquestions.org/questions/linux-general-1/help-needed-with-awk-704060/)

Help needed with awk

I am trying to extract information from a file using awk

e.g. My file

Code:

10001  aaa111  bbb222

10002  ccc333  ddd444

10003  eee555  fff666

If I want to extract information of 10001...

Code:

awk '/10001/ { print $1 " " $2 " " $3 }' myfile.txt

The above works. It outputs what i wanted

But if I want to hard code it and pass in the 10001 as a parameter into the script or using a variable...

Code:



mycode=10001



awk '/$mycode/ { print $1 " " $2 " " $3 }' myfile.txt

awk '/$1/ { print $1 " " $2 " " $3 }' myfile.txt

The above does not work. It does nothing and output nothing.
Is there something wrong with it?
I can't figure out why.

You have to put $mycode outside single quotes, otherwise it is not processed by the shell:

Code:

awk '/'$mycode'/ { print $1 " " $2 " " $3 }' myfile.txt

See the Awk Programming Guide about Using Shell Variables in awk programs, for further details.

The '$' sign which u r actually using has a different meaning in awk. I think, the site mentioned below would assist u in solving the problem.

http://www.vectorsite.net/tsawk_2.html#m2

Bye & Good Luck

The $mycode variable in post #2 is evaluated by the shell before the arguments are filled out.

Code:

set awk '/'$mycode'/ { print $1 " " $2 " " $3 }' myfile.txt

> echo $1

awk

> echo $2

/1001/ { print $1 " " $2 " " $3 }

> echo $@

awk /1001/ { print $1 " " $2 " " $3 } myfile.txt

Pay attention to what is inside the single quotes and what isn't.