cat

Print and concatenate files. More information: https://keith.github.io/xcode-man-pages/cat.1.html.

cat path/to/file

cat path/to/file1 path/to/file2 ... > path/to/output_file

cat path/to/file1 path/to/file2 ... >> path/to/output_file

cat -u /dev/tty12 > /dev/tty13

cat - > path/to/file

cat -n path/to/file

cat -v -t -e path/to/file