concatenate files and print on the standard output

Concatenate FILE(s), or standard input, to standard output.

With no FILE, or when FILE is -, read standard input.

-t     equivalent to -vT

-A, --show-all
       equivalent to -vET

-e     equivalent to -vE

-s, --squeeze-blank
       suppress repeated empty output lines

-E, --show-ends
       display $ at end of each line

-n, --number
       number all output lines

-T, --show-tabs
       display TAB characters as ^I