See Executable envelopes#Transfer-encoded executables for other executable formats of this sort.
- Convert a COM file to an ASCII-only COM file that runs like the original.
- Convert an EXE file to an ASCII-only COM file that, when executed, writes the original EXE file to a temporary disk file, then executes it. Only small EXE files are supported.
- Old versions (e.g. 2.2a) have a "self-extracting file" option (
-x). It produces an ASCII-only COM file that, when executed, writes the original (generally non-executable) file to disk. Later, this feature was moved to a separate NETSEND utility.
The ASCII-encoded files are normally wrapped in some plain text instructions, telling you to use a text editor to save the payload data to a .COM file. There is a
-z option to omit the wrapper, producing a file that can be executed directly (though you may have to rename it to end in ".COM").
Ignoring any wrapper, files made by older versions (e.g. 2.2a) start with "
COM-PRG.COM". This does not distinguish them from some files made by NETPIC (v1.0 with
-w option). For NETRUN v2.2a, "
NETRUN" appears at offset 151.
Ignoring any wrapper, files made by newer versions (e.g. 3.10) begin with "
XPPPYZIQD". This does not distinguish them from NETSEND and some NETPIC files. It's not clear how to reliably do that. For v3.10, at least, "
(c)1995.JIM.TUCKER" appears at offset 128.