srzip 0.3 - Manual


Stepan Roh

Version 0.3
Document revision 1.1 (2005/01/15)

Usage

Srzip is designated rather for fun than for work. It presents almost faithful copy of compression utilities gzip and bzip2, but with a slightly worse compression algorithms.

Srzip gets individual files from command line (or standard input) and replaces them with compressed version (if not said otherwise). Original files are deleted. If it is run as srunzip than it does decompression (in case of srzip it is necessary to use switch -d). If it is run as srzcat all files are decompressed on standard output and left unchanged.

Compressed files can be composed from more parts joined together without a gap.

If it is not permitted to take name of original file from compressed file header than it is constructed like this: at first it is tried to rip off the extension (default is .srz or specified with switch -S) or one-letter suffix 'z' and resulting name is shortened if system does not support long names.

Format of execution is: 

srzip [file names and switches in arbitrary order]

 switches:

 -a --ascii       end-of-lines conversion
 -c --stdout      write on standard output (activates --keep)
 -d --decompress  decompression
 -f --force       overwrite output files without a question
 -h --help        help
 -k --keep        keep original files untouched
 -l --list        list information about compressed files
 -L --license     "license" information
 -n --noname      do not store nor restore original file name or time
 -N --name        store and restore original file name and time
 -q --quiet       suppress all warnings
 -S .suf  --suffix .suf      use extension .suf when compressing
 -t --test        test compressed file integrity
 -v --verbose     be more verbose
 -V --version     version number
 -z --compress    compression
 -1 --fast .. -9 --best      compression level
 -m m --method m  compression method (0 = cpy, 1 = rle, 2 = shc, 3 = ahc, 4 = bwt)

Switches can be in short format (begin with '-'), long GNU format (begin with '+') and long POSIX format (begin with '--'). All these format are fully supported.

And now switches in deeper detail:

-a --ascii
End-of-lines are converted during compression and decompression. Must be used in both because on decompression Unix end-of-lines are presumed.
-c --stdout
Instead of creating some files, whole output is redirected to standard output. Original files are left unchanged and all normal output is suppressed. Output to terminal is refused unless switch -f is used.
-d --decompress
Decompression. Implicit mode if program is called srunzip (e.g. symbolic link is used). If switch -v is used, information about what is decompessed is printed.
-f --force
Output files are overwritten without a question. Also the fact that compressed file is decompressed on terminal is ignored.
-h --help
Help.
-k --keep
Original files are left untouched.
-l --list
For each compressed file it prints the original length and new length in bytes, compression ratio and file name for decompression. If switch -v is used the compression method name, control checksum and file time are printed too.
-L --license
"License" information.
-n --noname
No file name nor time is stored at compression. During decompression file name and time stored in the archive are ignored. By default it is ignored at decompression.
-N --name
File name and time are stored at compression. During decompression file name and time stored in the archive are used. By default it is stored at compression.
-q --quiet
All warnings are suppressed.
-S .suf --suffix .suf
Use given extension instead of standard '.srz'.
-t --test
Test archive integrity by trial in-memory decompression.
-v --verbose
Be more verbose.
-V --version
Program version.
-z --compress
Compression. Default mode of operation if program is called srzip. If switch -v is used, information about what is compressed is printed.
-1 --fast .. -9 --best
Compression level. Higher number = higher quality, lower number = higher speed.
-m m --method m
Compression method. By default it is the one with highest number. Is automatically detected at decompression. Available methods are:
0 = cpy
plain copy
1 = rle
run-length encoding (worst, but quickest)
2 = shc
static huffman coding
3 = ahc
adaptive huffman coding
4 = bwt
Burrows-Wheeler transformation (in fact BWT+MTF+AHC; best, but very slow compression, better than gzip)

Changes between versions

Changes from version 0.2 (2000/02/22) to version 0.3 (2000/05/03)

Changes from version 0.1 (1999/02/28) to version 0.2 (2000/02/22)

Improvements for the future

Stepan Roh <src@post.cz>

This document was generated using AFT v5.095