External variable in awk

Question

I have a script, in which a script snippet is:

x=3
awk \'$2=$x{print $1}\' infile

The external variable is x,

but it p

Answer 1

You pass an external variable for use in awk with the -v option:

some_variable=3
awk -v x=$some_variable '$2 == x {print $1}' infile

Also note that you need to change your code from $2=$x to $2 == x

• Use == instead =: the latter is assignment
• Do not prefix normal variables with $ inside the awk script.

Aside: You need to specify one -v for each variable you want to pass in, e.g:

var1=2
var2=4
awk -v x=$var1 -v y=$var2 '$2 == x {print y " " $1}' infile