Write to standard output corresponding lines of each file, separated by a tab.
paste file1 file2 [. . .]
-s pastes the lines from one file at a time, instead of one line from each file.
-d delim uses delimiters from the list of characters, instead of a tab.
- causes paste to use standard input as a file.
The paste command takes one line from each of the listed files and writes them out to standard output, separated by a tab. With the -s option, the paste command can also concatenate all lines from one file into a single gigantic line.