Linux Pocket Guide, 2nd Edition

Screen Output

echo	Print simple text on standard output.
printf	Print formatted text on standard output.
yes	Print repeated text on standard output.
seq	Print a sequence of numbers on standard output.
clear	Clear the screen or window.

Linux provides several commands for printing messages on standard output:

$ echo hello world
hello world

Each command has different strengths and intended purposes. These commands are invaluable for learning about Linux, debugging problems, writing shell scripts (see Programming with Shell Scripts), or just talking to yourself.