cat (concatenate and output files)
Use cat to output one or more files on the command line, for example:
cat file1 file2 file3
This will print the contents of the three files given on the terminal. Since the files are output in the order in which they appear on the command line, one could say that cat “concatenates” files, hence its name. cat's output is often redirected to a file, like so:
cat file1 file2 > file3
This will concatenate file1 and file2, saving the result in file3.