How can I create a table from key-value pairs?

Question

I want to check the differences between lots of key value pairs. I know I could write some code to do this, but I feel there is going to be an easier way to accomplish this. These values come from HTTP request URLs.

Say I have the following key value pairs, they are not always in order:

Set 1:

a=1
b=2
c=3

Set 2:

a=2
c=5
b=7

Set 3:

b=5
c=2
a=8

Set 4:

a=1
c=6
b=7

I'm looking for an output like this, just so I can easily see differences:

How can I achieve this easily, without having to write my own program?

Answer 1

You could use awk for this:

cat file1 file2 | awk -F "=" '{i[$1]=(i[$1] " " $2)} END {for (key in i) { print key " " i[key]}}'

Example output:

d  104 42
a  8 9
b  9 13
c  22 -1

Additionally pipe to sort if you want the values in a consistent order.