dm unar
'dm unar' is named after the well known unix command line tool, unar, and can be used to unarchive any of the native CBM single file archive formats that are also supported in DirMaster, including .arc, .ark, .cvt, .lbr, .lha, .lnx, .sda, .sfx, .spy, and .wr3. The results are stored on a new disk image (a d64 or d81). If you don't provide an extension for the disk, unar defaults to d64 but uses a d81 if necessary. dm can identify most archive formats so it usually isn't necessary that the archive file have a matching extension - therefore prg files can be unarchived directly without renaming and even misnamed archive files should be correctly unarchived.
Examples
Unarchive a Lynx file onto a new .d64, "disk.d64"
dm unar sb146644.lnx disk.d64
Unarchive a Wraptor file onto a new .d64, "disk.d64"
dm unar scrapit.wr3.prg disk