How do I pipe a file line by line into multiple read variables?

Question

I have a file that contains information in two columns:

box1 a1 box2 a2 

I'm trying to read this file line by line into read and have each line items be put into a variable.

On the first pass, $a would contain box1 and $b would contain a1.

On the second pass, $a would contain box2 and $b would contain a2, etc.

An example of the code that I am using to try to achieve is this:

for i in text.txt; do     while read line; do         echo $line | read a b;     done < text.txt;     echo $a $b; done 

This gives me the following results:

box1 a1 box2 a2 

When I expected the following results:

box1 a1 box2 a1 

How can I fix this?

Answer 1

Piping into a read command causes the variables to be set in a subshell, which makes them inaccessible (indeed, they are gone) to the rest of your code. In this case, though, you don't even need the for loop or the second read command:

while read -r a b; do     echo "$a" "$b" done < text.txt