mus is a program which invokes the MicroSED functionality in manner convenient to script writers. Generally, for scripting work, SED is to be prefered to mus because SED is a more complete implementation of the SED language. However, MicroSED scripts are not a pure subset of SED and so an executable that can be invoked from bourne shell scripts, or other, is needed to complete the toolset.
mus is basically like sed except that it does not support labels or any of the commands that involve them and (at the time of this writing) does not support the commands like "n" which force the reading of the next line of input.
MicroSED does implement an additional command, W, which stands for "while" that lets the script repeatedly process the current line of input while a given regular expression remains true. This is most helpful in the situation where the entire file has been concatenated into a single long line and then you want to perform some sort of repeated processing on that line.
Use the "-h" or "--help" command options to get help.