The echo command is as specified in the Single UNIX Specification but with the following differences.
Unlike the behavior specified in the Single UNIX Specification, whether echo supports options is implementation defined. The behavior of echo if any arguments contain backslashes is also implementation defined. Applications shall not run echo with a first argument starting with a hyphen, or with any arguments containing backslashes; they shall use printf in those cases. [1]
| [1] | The behavior specified here is similar to that specified by the Single UNIX Specification version 3 without the XSI option. However, the LSB forbids all options and the latter forbids only -n. |