Format Chart

I am providing the format decoding/encoding chart from the Mac-FTP-list as an aid for those who only want to know 'Which program will unmangle/uncompress this format?' Unlike the Mac-FTP-list this will be updated only as needed.

N = Cannot decompress .sit dlx {Type SITD} files
D = Decode only
X = Encode and decode

.sit refers to both 1.5 and dlx. Otherwise a '/' is used {1.5/dlx}.
.hqx = BinHex4; .bin = MacBinary (BinHex5)
Note: Almost every Mac communications program can decode .bin files.

*   .b64/.mime (Base 64) refers to the encoding format used by the 
    Multipurpose Internet Mail Extension.  For more information consult
    the MIME FAQ.
**  **  DropStuff with Expander Enhancer is an $30 shareware addon for Stuffit
    Expander.  The Stuffit Engine which comes with DSEE is also used by 
    other programs {marked with a *^}.  Current public versions are are 4.0 
    and 4.5 respectively DSEE version 4.5 is only available with StuffIt 
    Deluxe 4.5 as of this writing.
*** Stuffit Deluxe 3.5/4.0 translators can be used with Stuffit Lite.
    Current versions are 4.5.0 and 3.6.0 respectively as of this writing.

Other formats

.arj

PC format common to European sites. Decompressed by unArjMac, DeArj, and SITEX10.EXE (win).

.dd

Disk Doubler {Mac} format. Decompressed by DDExpand and DiskDoubler.

.exe

DOS/Windows executable file (program); also used to create self-extracting archives. An .exe file used as a self-extracting archive can usually be decompressed with Stuffit Expander w/ DSEE.

.html (.htm)

WWW document. Used by WWW browsers such as Netscape and lynx.

.image/.img/.ima/

These are all disk image extensions. They represent Mac disk image (.image/.img), Microsoft Disk Image Utility (.img), and Winimage (.ima) formats. Most can be decoded and/or mounted via StuffIt Engine 4.5 (part of StuffIt Deluxe 4.5) or ShrinkWrap 3.0. For a history of Shrinkwrap consult the 2.1 site.
Note that .img is also used as an graphic file extension and needs GraphicConverter to view.

.lzh (related formats - .lha and .lzs)

old PC/Amiga format that is still quite popular in Japan, largely replaced by .arc and .zip elsewhere; decompressed via the Stuffit Engine 4.5 and StuffIt Deluxe 4.5, macunpack, LHA Expander 1.0.3, French KISS 2.2.0 and MacLHA 2.2.1 (which also allows compression).

.pit

old {~1989} Mac compression format created by PackIt programs, replaced by .sit. In general, a program that handles .sit files can decompress .pit files as well.

.pkg

AppleLink package format, replaced by .sit. Decompressed by all present Mac StuffIt programs.

.rar

A DOS compression format. Decompressed by MacUnRAR.

.sea

A special version of a Mac compression format that decompresses itself when opened. The most common .sea files are Stuffit, Compact Pro, and Disk Doubler. On the PC Stuffit Expander for Windows will expand Stuffit SEA files.

.shar

Unix shell archive. Decoded by Unshar.

.taz

another name for .tar.Z

.tgz

another name for .tar.z and .tar.gz {do not confuse with .tar.Z}.

.txt (.abs)

.ASCII text file. There is a slight differance between the ASCII text files of Mac, PCs, and UNIX systems which can cause problems trying to read them. Mac ASCII uses carriage returns, UNIX uses line feeds, and PC uses both.

.z

Early {~1993} suffix for Gzip files. Due to confusion with the UNIX 'compress' suffix {.Z} it was abandoned in favor of the .gz suffix.

.zoo

old {~1989} PC/Amiga format, replaced by .arc. Decompressed by MacZoo and MacBooz.

CAUTION: While Gzip is aimed at replacing the .Z format, they are _different_ unix compression formats, and the suffixes are NOT inchangable. Many sites now support on-the-fly translation of these formats; just type in the file name minus the .Z or .gz suffix.

WARNING: .hqx, .txt, and .uu files are the ONLY files that can be downloaded in ASCII mode; all others must be downloaded in BINARY {IMAGE} mode for the file to decompress properly. This is especially true of ".bin" and "unpacked" files. Otherwise you will get errors like "unreadable file" or "file is corrupt" when you try to decompress them.

If you need further information please check out the comp.compression FAQ or David Lemson's compression chart