Horizontal file concatenation

Question

Is there a Linux command like cat that joins files with the same number of lines horizontally?

Answer 1

paste may do the trick.

% cat t1 
a
b
c
c
d
f
g
% cat t2 
h
i
j
k
l
m
n
% paste t1 t2 
a       h
b       i
c       j
c       k
d       l
f       m
g       n

At least some of the time, you don't need to have a "key" to concatenate the lines.

Answer 2

join should do the trick - You just need to prefix the lines with an identical ID.