4DOS compressed batch file

File Format
Name	4DOS compressed batch file
Ontology	Electronic File Formats Executables 4DOS compressed batch file
Extension(s)	.btm
Released	1993

The 4DOS command interpreter supports a compressed form of its batch files. Batch files can be compressed using the included BATCOMP.EXE utility.

Note that the .BTM file extension is not an indicator of compression. Most .BTM files are not compressed, and are covered in the Batch file article.

[TODO: 4DOS's quasi-successor Take Command Console (Wikipedia article) also supports batch file compression. Is the format the same?]

Identification

Files in the original (4DOS 5.0) format start with bytes 0xeb 0xbe.

Files in the newer (4DOS 6.02) format start with bytes 0xbe 0xeb.

Specifications

• See the comments in SOURCE/4DOS/SOURCES/BATCOMP.C, in the 4DOS open source versions.
• 4dec101.zip → README.TXT, VER100.DOC

Software

• BATCOMP.EXE - Included with 4DOS (compression only)
• 4DOS: Source code, Downloads
• 4DECOMP v1.0 (1993) - Decompresses old format (DOS software)
• 4DECOMP v1.01 (1999) - Decompresses old and new format (DOS software)
• UCOMPBTM (1993) - Decompresses old format (DOS software)

Sample files

• https://telparia.com/fileFormatSamples/document/4DOSCompressedBatch/

Links

• Wikipedia: 4DOS
• Take Command: Batch File Compression