gyaresu@zomg:~$ whatis paste
paste (1)            - merge lines of files

gyaresu@zomg:~$ whatis nl
nl (1)               - number lines of files


gyaresu@zomg:~$ cat a.txt
thing
stuff
ptang

gyaresu@zomg:~$ cat b.txt
yellow
blue
pink

gyaresu@zomg:~$ paste a.txt b.txt > c.txt

gyaresu@zomg:~$ nl c.txt
1   thing   yellow
2   stuff   blue
3   ptang   pink