cheat sheets.

Puts lines from two files together, either lines of each file side by side
(normally separated by a tab-stop but you can have any symbols(s) you like...)
or it can have words from each file (the first file then the second file) side
by side.

To obtain a list of lines side by side, the first lines from the first file on
the left side separated by a tab-stop then the first lines from the second file.
You would type:
$  paste file1.txt file2.txt

To have the list displayed in serial, first line from first file, [Tab], second
line from first file, then third and fourth until the end of the first file
type:
$  paste --serial file1.txt file2.txt