Provided by: arc_5.21p-1_i386 bug

NAME

       arc - pc archive utility

SYNOPSIS

       arc  a|m|u|f|d|x|e|r|p|l|v|t|c  [  biswnoq  ]  [  gpassword ] archive [
       filename ...]

DESCRIPTION

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

INSTRUCTIONS

       Execute arc with no arguments for fairly verbose, usable instructions.

COMMAND SWITCHES

       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.

       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.

OPTIONS

       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.

       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.

PROGRAMMING NOTES

       Arc 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 unnecessary.  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" ARC programs.

       Arc will look for environment variables named ARCTEMP or TMPDIR, 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.

HISTORY

       Arc  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  arc  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.

BUGS

       Arc  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 arc 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 arcing them.

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

            hyc@hanauma.jpl.nasa.gov

AUTHORS

       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 (ddl@harvard.edu) Ported from MSDOS
       by Howard Chu, with help from John Gilmore (hoptoad!gnu), James  Turner
       (daisy!turner) and others.