Category : C Source Code
Archive   : ARC521_C.ZIP
Filename : ARC.DOC

AAARRRCCC(((111LLL))) LLLooocccaaalll (((111222 JJJuuunnn 111999888888))) AAARRRCCC(((111LLL)))



NNNAAAMMMEEE
arc - pc archive utility

SSSYYYNNNOOOPPPSSSIIISSS
aaaarrrrcccc a|m|u|f|d|x|e|r|p|l|v|t|c [ biswnoq ] [ g_p_a_s_s_w_o_r_d ]
_a_r_c_h_i_v_e [ _f_i_l_e_n_a_m_e ...]

DDDEEESSSCCCRRRIIIPPPTTTIIIOOONNN
_A_r_c is a general archive and file compression utility, used
to maintain a compressed archive of files. An _a_r_c_h_i_v_e is a
single file that combines many files, reducing storage space
and allowing multiple files to be handled as one. _A_r_c uses
one of several compression methods for each file within the
_a_r_c_h_i_v_e, based on whichever method yields the smallest
result.

IIINNNSSSTTTRRRUUUCCCTTTIIIOOONNNSSS
Execute _a_r_c with no arguments for fairly verbose, usable
instructions.

CCCOOOMMMMMMAAANNNDDD SSSWWWIIITTTCCCHHHEEESSS
a add files to archive. Copies the indicated files to the
archive.

m move files to archive. Same as 'a' switch except that
the files are deleted from the directory as they are
moved to the archive.

u update files in archive. This switch will replace
archived files when the named file is newer than the
archived copy. New files will be added automatically.

f freshen files in archive. Same as 'u' except that new
files will not be added.

d delete files in archive. The named files are removed
from the archive.

x,e
extract files from archive. The named files are
extracted from the archive and created in the current
directory in an uncompressed state.

r run one file with arguments from archive. Any program
may be executed directly from the archive. The
parameters given after the program name are passed to the
program without modification.

p copy files from archive to standard output. Useful with
I/O redirection. A form-feed is appended after each file,
to ease use with printers.




Page 1 (printed 8/1/88)






AAARRRCCC(((111LLL))) LLLooocccaaalll (((111222 JJJuuunnn 111999888888))) AAARRRCCC(((111LLL)))



l list files in archive. Limited information listing of
files contained in an archive. Displays the filename,
original length, and date last modified. If the 'n'
option (see below) is used, only the filename is
displayed.

v verbose listing of files in archive. Complete
information listing of files contained in an archive.
Displays the filename, original length, storage method,
storage factor (% savings), compressed size, date, time,
and CRC.

t test archive integrity. Computes CRC values for each
member of the archive and compares against the previously
saved value.

c convert entry to new packing method. Convert files
stored with older methods to newer methods that are more
efficient. Also useful for files previously archived with
the 's' option.

OOOPPPTTTIIIOOONNNSSS
b retain backup copy of archive. Keep the original archive
file and rename to .BAK. This switch may be used with
the following commands: a, m, u, f, d, c.

i suppress image mode. This switch causes files to be
treated as text files, and will translate their end-of-
line sequence. (Unix's '\n' vs. '\r\n' used on many other
systems.) The default is to perform no translation when
compressing or extracting files. This option makes
dealing with text files much nicer, though the 'tr'
command can also be used. ('\r' in makefiles and C source
code is such a nuisance...)

s suppress compression. This forces new files to be saved
using Method 2 (no compression). This switch may be used
with the following commands: a, m, u, f, c.

w suppress warning messages. This switch will keep warning
messages from being displayed which is the default. Most
warnings concern the deletion or existence of files with
the same name.

n suppress notes and comments. This switch will keep
useful notes from being displayed which is the default.
Most notes indicate what stage of compression is being
run (analyze, compaction, storage).

o overwrite existing files when extracting. This switch
will make existing files silently get overwritten,
instead of asking for confirmation, which is the default.



Page 2 (printed 8/1/88)






AAARRRCCC(((111LLL))) LLLooocccaaalll (((111222 JJJuuunnn 111999888888))) AAARRRCCC(((111LLL)))



q force Squash compression method. This switch causes the
Squash compression method to be used, instead of Crunch,
which is the default.

g encrypt/decrypt archive entry. This is used to encode
files so that others may not read them. BE CAREFUL!
This must be the last parameter in the switches because
everything following is part of the password.

PPPRRROOOGGGRRRAAAMMMMMMIIINNNGGG NNNOOOTTTEEESSS
_A_r_c Version 2 differs from version 1 in that archive entries
are automatically compressed when they are added to the
archive, making a separate compression step unecessary. The
nature of the compression is indicated by the header version
number placed in each archive entry, as follows:
1 = Old style, no compression
2 = New style, no compression
3 = Compression of repeated characters only
4 = Compression of repeated characters plus Huffman SQueezing
5 = Lempel-Zev packing of repeated strings (old style)
6 = Lempel-Zev packing of repeated strings (new style)
7 = Lempel-Zev Williams packing with improved hash function
8 = Dynamic Lempel-Zev packing with adaptive reset
9 = Squashing

Type 5, Lempel-Zev packing, was added as of version 4.0

Type 6 is Lempel-Zev packing where runs of repeated
characters have been collapsed, and was added as of version
4.1

Type 7 is a variation of Lempel-Zev using a different hash
function which yields speed improvements of 20-25%, and was
added as of version 4.6

Type 8 is a different implementation of Lempel-Zev, using a
variable code size and an adaptive block reset, and was
added as of version 5.0

Type 9 is another variation of Lempel-Zev, using a larger
hash table. This method was developed by Phil Katz, and is
not supported by the "official" AAAARRRRCCCC programs.

_A_r_c will look for environment variables named _A_R_C_T_E_M_P or
_T_M_P_D_I_R, which, if present, indicates the pathname where
temporary files should be created. This is typically the
location of a RAMdisk on a microcomputer, "/tmp/" or left
unset.

See the included documentation file for more details.

HHHIIISSSTTTOOORRRYYY



PPPaaagggeee 333 (((ppprrriiinnnttteeeddd 888///111///888888)))






AAARRRCCC(((111LLL))) LLLooocccaaalll (((111222 JJJuuunnn 111999888888))) AAARRRCCC(((111LLL)))



_A_r_c has been in use in the CP/M and MSDOS world for many
years. Thom Henderson developed the original version, but
it is important to note that _a_r_c is based on the file
compression theories developed by Huffman, Welch, Knott,
Knuth, and many other scientists. This implementation is
based on version 5.21 of the MSDOS program.

BBBUUUGGGSSS
_A_r_c behaves just like the PC version of the program; all
functions of the "usage" display are working. Full
compatibility with PC ARC files is maintained, the price for
which is that _a_r_c doesn't like long filenames, and can only
archive files with names of up to 12 characters. It will
*sometimes* do The Right Thing with them, but I suggest you
put long-winded filenames in a "shar" before _a_r_cing them.

There shouldn't be any problems, (hah!) but if you find any,
please send them to me at:

[email protected] {rutgers, uunet}!umix!hyc


AAAUUUTTTHHHOOORRRSSS
Original MSDOS program by Thom Henderson
COPYRIGHT(C) 1985-87 by System Enhancement Associates; ALL
RIGHTS RESERVED

Original Lempel-Zev code derived from compress 4.0.
Modified to support Squashing by Dan Lanciani
([email protected]) Ported from MSDOS by Howard Chu
(umix!hyc), with help from John Gilmore (hoptoad!gnu), James
Turner (daisy!turner) and others.























Page 4 (printed 8/1/88)