quickie_svt(1)quickie_svt(1)NAMEquickie_svt - simple version tool
SYNOPSISquickie_svt-Check_Output -History file -File output-file [ -e edit ]
quickie_svt-Check_In -History file -File input-file
quickie_svt-List -History file
quickie_svt-Query -History file
quickie_svt-Version
DESCRIPTION
The quickie_svt program is used to manage Quickie's history version
files. Normally the quickie(1) CGI progran does this by itself, but
there may be times when a maintainer needs to access the history
directly. (It's also useful for testing.)
OPTIONS
The following options are understood:
-History history-file
This option is used to specify the name of the history file.
The usual suffix is ",svt".
-File file-name
This option is used to specify the name of the input or output
file. On checkout, the file name "-" is understood to mean the
standard output. There is no equivalent for checkin.
-Edit edit-number
This option is used to specify the edit number (version num‐
ber). On checkout, if no version number is specified, the most
recent version is given.
-Check_In
This option is used to check a file into the history.
-Check_Out
This option is used to checkout a file from the history.
-List This option is used to list the file's history.
-Query This option is used to query edit number of most recent
checkin.
-Version
This option is used to print version number.
All other options will produce a diagnostic error.
All options may be abbreviated; the abbreviation is documented as the
upper case letters, all lower case letters and underscores (_) are
optional. You must use consecutive sequences of optional letters.
All options are case insensitive, you may type them in upper case or
lower case or a combination of both, case is not important.
For example: the arguments "-project, "-PROJ" and "-p" are all inter‐
preted to mean the -Project option. The argument "-prj" will not be
understood, because consecutive optional characters were not supplied.
Options and other command line arguments may be mixed arbitrarily on
the command line, after the function selectors.
The GNU long option names are understood. Since all option names for
quickie_svt are long, this means ignoring the extra leading '-'. The
"--option=value" convention is also understood.
FILE FORMAT
Each version in the history file consists of an RFC822 header, plus the
file contents. The header includes (at least) the Content-Length, used
to remember the length of the file data in bytes; the Checksum, used to
remember the Adler32 checksum of the file data; and Version, used to
remember the version number. The file data can be text or binary,
because its length is determined by the header. There is no quoting
mechanism of any kind for the data. Except for the mandatory fields,
additional user-defined us-ascii meta-data may also be stored in the
header. There is no diff or delta of any kind for any version.
This combination of header and data has good end-to-end behaviour,
because there is a checksum to validate the file data against. Bad
blocks in the data will be detected then next time a checkin or check‐
out is attempted.
The format of the history file consists of one or more file versions
with the above layout, joined head-to-tail with no separators or bound‐
ary indicators of any kind. The versions are in descending order, from
most recent (greatest edit number) to least recent (version number
one). To determine where one version stops and the next version
starts, use the Content-Length field in the header. The entire history
file is then compressed using the GNU Zip algorithm (via zlib). There
is no diff or delta of any kind in the history file.
The advantage of compressing the file is that there is usually a very
high redundancy between file versions. For example, if two identical
versions are checked in (not necessarily sequentially) the second copy
will compress to only a few bytes. Unlike diff(1) style deltas, this
also copes very will with moving blocks of data within the file. The
use of GNU Zip formatting means there is also a checksum for the whole
history file, which allows you to detect bad blocks in the header por‐
tions; it also means there is a simple way to extract the data from a
history file even without the quickie_svt program, or for testing, or
because you are curious.
This style of history file was inspired by RFC 3284 - The VCDIFF
Generic Differencing and Compression Data Format. While the
quickie_svt format does not use RFC3284 internally, the arguments for
compression across file versions in still relevant.
EXIT STATUS
The quickie_svt command will exit with a status of 1 on any error. The
quickie_svt command will only exit with a status of 0 if there are no
errors.
COPYRIGHTquickie_svt version 1.1
Copyright (C) 2005, 2006 Peter Miller;
All rights reserved.
The quickie_svt program comes with ABSOLUTELY NO WARRANTY; for details
use the 'quickie_svt -VERSion License' command. This is free software
and you are welcome to redistribute it under certain conditions; for
details use the 'quickie_svt -VERSion License' command.
AUTHOR
Peter Miller E-Mail: millerp@canb.auug.org.au
/\/\* WWW: http://www.canb.auug.org.au/~millerp/
Reference Manual Quickie quickie_svt(1)
