7. SO NOW YOU HAVE THE FILE WHAT DOES THE EXTENSION MEAN

Most files that are stored on FTP machines have some sort of extension. These normally relate to either the compression program used or the type of data stored in the file. Here are the more common compression programs you will come across in the Amiga world (there are many others in other worlds):-

• .lzh = lharc,lz, lha,lharca
• .lha = LhA (Sometimes LZ - Also does lzh files)
• .lzx = Lzx (Similar to LhA, but not compatible)
• .zoo = zoo
• .lhw = lhwarp
• .arc = arc (hardly used)
• .arj = arj
• .dms = dms (Diskmasher)
• .wrp = Warp files
• .zip = Zipped, use "zippy" program
• .gz = PC zip like program
• .Z = Compress (found on unix systems)
• .tar = tape archive (found on unix systems, example: tele.tar.Z)
• .zom = zoom!
• .pp = powerpacker (data files only)
• .zap ="Disk Zapper"?
• .uue = uuencode (Amiga version of unix thing...)
• .zuu = UUencoded ZOO file
• .auu = UUencoded ARC file
• .luu = UUencoded LHARC file
• .hqx = BinHqx
• .sit = Stuffit
• .pak = Pak files unpack themselves. Just run them.
• .sfx = Self extracting.
• .run = Self extracting.

Also many applications use extensions to highlight the type of file, so you will see things like .gif, .iff, .txt, .doc.., The list can go on and on. You will probably see quite a few as you begin to use Archie.

Of these, probably .lha and .dms seem to be the most popular. LhA is used to compress most programs, and these archives can be unpacked to any device. DMS is used to compress entire disks, and they must be decompressed to a blank disk.

If you meet a file.tar.Z file on a Unix system, the uncompress MUST be carried out prior to issuing 'tar' command, ie. the last level was the last function carried out. You must work in reverse order. There is a 'compress-4.0.lzh on some of the FTP machines around that works on Amigas, to uncompress using this command use:-

       compress -d filename

Beware of .dms files. Dms allows a boot block to be compressed and hence downloaded. This is one method of spreading viruses! Other compressor/archivers may do also. However, DMS does have a facility to view non-standard bootblocks, so you can generally tell if you might be getting a virus.

There are a couple of utilites that are very useful regarding compression and archive files:-

util/arc/LhA_e138.run       LhA evaluation version.
  "   " /Lister12.lha       Lists contents of various archive types.
  "   " /lzx120.lha         File archiver with better compression than LhA
  "   " /DeTar12.lha        Untars unix archives.
  "   " /dms111.run         Extracts .dms files to floppy disks.
util/pack/compress-4.0.lzh  Decompresses unix .Z files.
  "   "  /Extractor.lzh     UUdecodes files.
  "   "  /gzip124x2.lha     Decompresses .Z and .gz files.
  "   "  /imploder-4.0.lzh  A good program (de)compressor.
  "   "  /xfd107.lha        Decompress files automatically.
  "   "  /xpk25usr.lha      Very good compression package.

The essential utilities are LhA and DMS, whilst gzip and detar can be useful if you use files other than amiga specific ones.

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