SpartaDOS X Reference Manual

The Command Processor — Commands

Index

The "arcfname" is the file name of the archive. The "filelist" is the list of files to be added, deleted, updated, extracted, etc., to or from the archive. Leave a space between each filename in the filelist. Wildcards are perfectly legal. If no filelist is entered, "*.*" is assumed.

"Command" is one of the following:

A		Add file(s) to the archive. Add all files from the file list to the archive.
M		Move file(s) to the archive. Move deletes the source file once it has been added to the archive.
U		Update file(s) in the archive. Update will look at the date of the files in the archive, replacing files with a newer date, and add all files (from filelist) which do not currently exist in the archive.
F		Freshen file(s) in archive. This is the same as update but without the "add" feature. Freshen will replace the older files in the archive with any newer files of the same name.
D		Delete file(s) from the archive. Delete will remove the files listed in the filelist from the archive.
X,E		Extract file(s) from the archive. Both allow you to extract files from an archive. The method(s) of file compression used when creating the archive is reversed and the files specified in the filelist are restored to their original state.
P		Print file(s) to the screen. This allows you to examine the contents of files within an archive without extracting them. Of course this can be diverted to other devices with redirection; for example,     ARC P MYARC READ.ME >>PRN: will divert the contents of "READ.ME" from the archive "MYARC" to your printer.
L		List file(s) in archive. This shows the filename, original file length, and date/time created of each file in the archive as well as the number of files and total size of files if extracted.
V		Verbose list of file(s) in archive. This command shows the filename, original file length, number of files, and total size, just as the L command does. Instead of date and time created, however, the V command shows stowage method, stowage factor (percent of space saved), the file size now, and the total size now.

Valid options are:

B		Retain a backup copy of the archive. This is a safety option for the A, M, U, F, and D commands. The B option will result in a backup of the old archive with the extension of ".BAK" as well as the new archive.
S		Suppress compression. This will archive files without compressing them. Most people will not use this option but it is faster than using compression.
W		Suppress warning messages. Use this command sparingly if at all. This will prevent those unsightly errors from being displayed but will also prevent mistakes from being discovered and avoided.
N		Suppress notes and comments. This will suppress the display of the standard ARC screen output which shows the current file being compressed or extracted, the compression method used, etc.
H		High speed. With the screen off on the Atari, processing speed is increased 20% to 30%. If you wish to go faster but don't need to see the screen, use this option. The screen display will return when finished.
G		Encrypt/decrypt an archive entry. This prevents others from reading your files. G must be the last option and must be followed by a password. If you forget your password, you will not have a useful archive. For example,     ARC AHGICD STUFF WASTE.DOC WASTE.COM READ.ME In the preceding example the three files in the file list would be added into the archive called "STUFF.ARC" under the password of "ICD" with the screen off.

Archive entries are always saved in alphabetical order. This sorting function puts a practical limit of about 80 files per archive on 64K machines (USE OSRAM) and 180 files per archive on computers which use the extended memory mode (USE BANKED). ARC will not run on 48K machines unless they have an AXLON compatible memory upgrade installed. Archive entries do not save pathnames which means duplicate file names are not allowed (one will replace the other).

ARC is very useful for saving time while uploading/downloading files with a MODEM and saving space for archival storage. ARC uses four stowage methods and automatically determines the best method(s) suited to each file. Our SpartaDOS X version of ARC is also fully compatible with ALFcrunched files, but it is highly recommended that you unARC an ALFed file and then ARC it before adding or updating. This will assure the most compact compression and arrange all files alphabetically within the archive. The four stowage methods used in ARC are as follows:

Stored — no compression used. This is mainly used with very short files.

Packed — Strings of repeated values are collapsed. All files are packed before other compression methods are attempted.

Squeezed — Huffman encoding compression. This is usually only effective with larger machine language files. Huffman encoding uses a weighted binary tree method assigning the lowest bit representations to the most commonly used characters.

Crunched — Dynamic Lempel-Ziv compression with adaptive reset. This is created on the fly and is stored as a series of bit codes which represent character strings. Crunched is one of the more effective methods used. ALFcrunch exclusively uses a variant of this method.

NOTICE: The name ARC, compatibility, and all other similarities to the ARC.EXE program by SEA (for MSDOS computers) are intentional. This trademark and the "look and feel" of the program have been licensed for SpartaDOS X by ICD, Inc. from SEA (System Enhancement Associates).

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