The cat command means concatenate, it allows us to view text in the terminal,
$ cat file.txt
or more than one file if one wants,
$ cat file1.txt file2.txt
and using the ‘>‘ command one bigfile.txt which is the union of the other 2 (or more)
$ cat file1.txt file2.txt > bigfile.txt
Note that it works for text files even if their extension is not .txt.