Com2txt
Com2txt is a utility that converts a DOS COM file to one whose bytes all belong to a certain set of ASCII characters, and which still has the same functionality. It was developed by Naoyuki Nide. Most of the information about it is in Japanese.
It's a silly hack, but it had some practical uses, such as for embedding a COM file in a Batch file, email, etc.
It has a -r option, to recover the original file.
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Disambiguation
Not to be confused with Com2txt (Dark Stalker).
For other software with a similar name or function, see Executable envelopes#Transfer-encoded executables.
Identification
Assuming version 1.11 is the last, and that it can decode all the formats, there are a total of three formats, which we'll call old, new-default, and new-alternate.
Old files (e.g. from v1.00) start with "TXPPP".
New-default files (e.g. from v1.11) start with a roughly 200-byte prefix that begins "T_OOWW3=XXWX" (see the HDR_DATA.C source file). The signature "com2txt/Nide" also appears in the standard prefix, but is less reliable for format identification.
New-alternate format is enabled with the -c option (undocumented in English). It is named something like "com-batch shared format". The format begins ":=%00%AA5$QP".
Software
- com2txt v1.11 (DOS binary + source code)
Sample files
- xpa167m.zip → *.COM (files have a customized signature)
