Implementations of `echo(1)`

Based on the Open Group POSIX specification.

Why?

For fun
For sysadmins who need strictly compatible versions of echo
For someone who just "wants echo to work, damnit"
For reference
To demonstrate the difficulty of POSIX echo(1)

Compiling

Build binaries with a POSIX-compatible make(1). Individual targets are provided for the implementations listed below.

Supported Implementations

POSIX
BSD
XSI
SystemV

Bugs

No account for environment variables, e.g., LANG and LC_*
Limited error checking
No make(1) support for installation, out-of-source building, documentation
No tests
No documentation

If you find a bug, particularly in the implementation of the POSIX standard, please file an issue.