Table of Contents

About

Echo in bash.

Echo accepts an argument (a literal string or a variable) as standard input, and echoes it back to the terminal as standard output.

In Bash, it's available as:

You can also use Bash - printf (Builtin command) for complex formating

Management

How to test if it's the built-in function and not the utility

echo is a builtin bash command

with the type command 

type echo

echo is a shell builtin

Echo the standard streams (input)

echo 1 2 3 4 | echo $(</dev/stdin)

1 2 3 4