Section: User Commands (1)


dact - compress or expand a file or stream 


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 ...] 


DACTreduces input files by attempting to compress each blockof the file with several different algorithms and selects thebest one for each block.



Decompress the file (or stdin, if no file is given), removingthe extension if it has a valid one.
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, Compression ratio (uncompressed to compressed), File's original name, CRCs (if available).
Force bad and unsafe things to happen. Can be combined tomake even worse things happen. One `-f' allows overwriting ofexisting files, two `-f' allows you to ignore bad magic andCRC check fails.
Send output to stdout, this will allow you to force DACT tosend compressed output to a terminal or result of compressinga file to a pipe.
Increase verbosity, can be combined to increase verbosity alot. Currently, only up to 3 makes sense. One `-v' displaysa bar graph. Two `-v' displays a bar graph and blockinformation. Three `-v' displays a bar graph and detailedcompression statistics per block.
List compression algorithms available.
Toggle use of CRCs. This option is especially useful whencombined with the network capabilities of DACT. It allowsyou to create a compressed file with only the header pointingto a web page that contains the real DACT file (whichnormally has its CRCs checked against the compressed headerto ensure they're the same file), with this option the filesdo not have to be from the same source (i.e., you can havean updated copy automatically extend itself.)
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."
Complain when compression errors occur. When a block isselected, it is tested to ensure that it decompresses backto the original source. If it fails, the algorithm is notused, with this option you are informed of the failure.
Write only header (no data). This option is useful fordistributing archives that need only reside on the internetsomeplace.
Toggle writing original file name in the DACT header. Thishas no real use that I know of.
Use speed-size as a metric rather than size. This is notimplemented yet. This will make DACT create an optimizedcompressed file, balancing speed of decompression with size.
Give usage synopsis.
Display DACT version.
Upgrade DACT. This option will fetch the latest binary fromthe internet and place it in $HOME/.dact/ as dact.bin. Ifyou have `binary_check on' in your dact.conf file, DACT willcheck for this file and use it. If you have Debian and run`dact -N' as root the Debian upgrade procedure will upgradeyour entire system.
DACT modules. This option will fetch the latest modules from the internet and place them in $HOME/.dact/ in a subdirectory corresponding to your Operating System and CPU Architecture.
-b size
Use the specified block size to compress the file. Thesize parameters is in bytes.
-e num
Exclude an algorithm from being used. This option is usefulif you know your target will not be able to decompress acertain algorithm (you can get their numbers from the `-l'option.)
-m file
Load another config file. This option will attempt to loadthe specified file in addition to the normal files, theoptions in this file will supersede other options.
-o file
Alternate output. This option sends output to a file insteadof INFILE.dct. The file can also be a URL or '-' for standardout.
-u url
This option will encode an URL in the compressed file's header,this URL will be tried (and CRCs checked) before attempting todecompress 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 values 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 `@'
    dact -p
-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 thecompressed file.
-I num
Use only 1 algorithm (and uncompressed as a fall-back), usefulif you want to limit yourself to a certain type of compression.
-U file
Encode the specified file into the header of the compressedfile. This file will be searched (line-by-line) for a workingURL to download compressed content from. See also `-u.'
-E cipher
Enable encryption using the specified algorithm, differentalgorithms use different authentication methods.






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



Roy Keene<>




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