Shell Data Processing - Standard Input Stream (Stdin)

IO - Standard Input (stdin) in a shell

cat will start a standard input session

cat

You can redirect it to a file.

cat > myinput.txt

If your command needs plain input without terminal emulation you can use input redirection with a pipe like:

echo "some input" | command

Ctrl+D typed at the start of a line on a terminal, signifies the end of the file (input).

Example:

cat -

Type what you want then Ctrl+D