DACT(1)                                                                DACT(1)



NAME
       dact - compress or expand a file, or stream

SYNOPSIS
       dact  [  -dsfcvlniCHOShVNa  ]  [-b size]  [-e algo]  [-m file] [-o file] [-u url]
       [-p url] [-M command] [-D desc] [-I algo] [-U file] [-E cipher] [file ......]

DESCRIPTION
       DACT reduces input files by attempting to compress each  block  of  the
       file  with  several  different  algorithms and selects the best one for
       each block.


OPTIONS
       -d     Decompress the file (or stdin, if no file  is  given),  removing
              the extention if it has a valid one.

       -s     Display  statistics  about  the  file,  such as: Magic number of
              file, DACT version file was compressed with, Block size used  to
              compress  file, Compressed file size, Original file's size, Com-
              pression ratio (uncompressed  to  compressed),  File's  original
              name, CRCs (if available).

       -f     Force  bad and unsafe things to happen.  Can be combined to make
              even worse things happen.  One `-f' allows overwriting of exist-
              ing files, two `-f' allows you to ignore bad magic and CRC check
              fails.

       -c     Send output to stdout, this will allow you to force DACT to send
              compressed  output to a terminal or result of compressing a file
              to a pipe.

       -v     Increase verbosity, can be combined to increase verbosity a lot.
              Currently,  only  up  to 3 makes sense.  One `-v' displays a bar
              graph.  Two `-v' displays a bar  graph  and  block  information.
              Three `-v' displays a bar graph and detailed compression statis-
              tics per block.

       -l     List compression algorithms available.

       -n     Toggle use of CRCs.  This option is especially useful when  com-
              bined  with  the network capabilities of DACT.  It allows you to
              create a compressed file with only the header pointing to an web
              page  that  contains the real DACT file (which normally has it's
              CRCs checked against the compressed header to ensure they're the
              same  file),  with  this option the files do not have to be from
              the same source (i.e., you can have an  updated  copy  automati-
              cally extend itself.)

       -i     Read  input  from  standard  input instead of /dev/tty.  This is
              used to read user supplied information like encryption keys  and
              passwords  from  standard  input instead of the more appropriate
              method of opening "/dev/tty."

       -C     Complain  when  compression  errors  occur.   When  a  block  is
              selected,  it  is  tested to ensure that it decompresses back to
              the original source.  If it fails, the algorithm  is  not  used,
              with this option you are informed of the failure.

       -H     Write  only  header  (no  data).  This option is useful for dis-
              tributing archives that need only reside on the  internet  some-
              place.

       -O     Toggle  writing  original file name in the DACT header. This has
              no real use that I know of.

       -S     Use speed-size as a metric rather than size.  This is not imple-
              mented  yet.  This will make DACT create an optimized compressed
              file, balancing speed of decompression with size.

       -h     Give usage synopsis.

       -V     Display DACT version.

       -N     Upgrade DACT.  This option will fetch the latest binary from the
              internet  and place it in $HOME/.dact/ as dact.bin.  If you have
              `binary_check on' in your dact.conf file, DACT  will  check  for
              this file and use it.  If you have Debian and run `dact -N'   as
              root the Debian upgrade procedure will upgrade your entire  sys-
              tem.

       -a     DACT  modules.   This  option will fetch the latest modules from
              the internet and place them in $HOME/.dact/  in  a  subdirectory
              cooresponding to your Operating System and CPU Architecture.

       -b size
              Use  the  specified  block  size  to  compress  the  file.  This
              option's parameters is in bytes.

       -e num Exclude an algorithm from being used.  This option is useful  if
              you  know  your  target will not be able to decompress a certain
              algorithm (you can get their numbers from the `-l' option.)

       -m file
              Load another config file.  This option will attempt to load  the
              specified  file  in addition to the normal files, the options in
              this file will supercede other options.

       -o file
              Alternate output.  This option sends output to a file instead of
              INFILE.dct.  The file can also be a URL or '-' for standard out.

       -u url This option will encode an URL in the compressed file's  header,
              this  URL  will be tried (and CRCs checked) before attempting to
              decompress the data in the actual file.

       -p url URLs in DACT can have variables in them that  will  be  expanded
              when  network  access  is  required, this allows you to test the
              results of that extrapolation easily.  Variables and their  val-
              ues are:
                  @@OSNM@@        OS Name (linux, freebsd, sunos, etc)
                  @@OSVR@@        OS version (2.2.x, 4.2, 5.8, etc)
                  @@OSVS@@        OS version (short) (2.2, 4.2, 5.8, etc)
                  @@ARCH@@        Arch (i386, sparc64, sun4u, sun4m, etc)
                  @@DIST@@        If OSNM=Linux, distribution of Linux.
                  @@FILE@@        Name of compressed file.
                  @@DTVR@@        Version of DACT (maj.min.rev)
                  @@DTVS@@        Version of DACT (short) (maj.min)
                  @@PASS@@        Prompt for Password
                  @@USER@@        Prompt for Username
                  @@ATSN@@        Put an `@'
                example:
                  dact       -p       http://www.rkeene.org/devel/dact/precom-
              piled/dact-@@OSNM@@-@@OSVS@@-@@ARCH@@.bin
                  dact:     http://www.rkeene.org/devel/dact/precompiled/dact-
              linux-2.4-i586.bin

       -M command
              This  option  executes  a command from the command line as if it
              appeared in "dact.conf".

       -D desc
              Encode the description specified into the  header  of  the  com-
              pressed file.

       -I num Use  only  1 algorithm (and uncompressed as a fall-back), useful
              if you want to limit yourself to a certain type of  compression.

       -U file
              Encode  the  specified  file  into  the header of the compressed
              file.  This file will be searched (line-by-line) for  a  working
              URL to download compressed content from.  See also `-u.'

       -E cipher
              Enable encryption using the specified algorithm, different algo-
              rithms use different authentication methods.


FILES
         $HOME/.dact/
         $HOME/.dact/dact.conf
         /usr/etc/dact.conf


SEE ALSO
       gzip(1), bzip2(1), mcrypt(3)


AUTHOR
       Roy Keene <dact@rkeene.org>



                                                                       DACT(1)
