<code>echo</code> is a shell command that writes input text to standard output. It is available in many operating system and shells. It is often used in a shell script to log status, provide feedback to the user and for debugging. For an interactive session, output by default displays on the terminal screen, but output can be re-directed to a file or piped to another process. leaves the behavior unspecified if the first argument is <code>-n</code> or any argument contains backslash characters while the Unix specification (XSI option in POSIX) mandates the expansion of some sequences and does not allow any option processing. In practice, many <code>echo</code> implementations are not compliant in the default environment. Because of these variations, <code>echo</code> is considered a non-portable command

Further reading

  • Microsoft TechNet Echo article