88 lines
2.4 KiB
Text
88 lines
2.4 KiB
Text
.\" Copyright (C), 1995, Graeme W. Wilford. (Wilf.)
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.\" Copyright (c) 2002, 2007 Colin Watson.
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.\"
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.\" You may distribute under the terms of the GNU General Public
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.\" License as specified in the file docs/COPYING.GPLv2 that comes with the
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.\" man-db distribution.
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.\"
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.\" Thu Sep 21 19:22:47 BST 1995 Wilf. (G.Wilford@ee.surrey.ac.uk)
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.\"
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.BS 1 "Compression"
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.BS 2 "Compressed manual pages"
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.lp
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It is possible to maintain a system of compressed manual pages.
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This imposes a small overhead on the formatting process, but is nevertheless
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usually reasonable in order to avoid unnecessary consumption of disk space.
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.lp
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Presently, the compression extension/decompressor pairs must be known at
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compile time although any number may be defined and used.
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The following structure is predefined in \*M:
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.TS
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center box tab(@);
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l | l .
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Extension@Decompressor
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_
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gz@gzip \-dc
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z@gzip \-dc
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Z@compress \-dc
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.TE
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It is a relatively easy operation to include further pairs in this
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structure.
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See
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.i lib/compression.c
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for details and an example.
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.lp
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Support for compressed manual pages is compiled into the \*M utilities by
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default, depending on the decompressors available at configure time.
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.BS 2 "Compressed cat pages"
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.lp
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\*M compresses cat files by default.
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During configuration,
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.b configure
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will try to find
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.b gzip
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and, if found, all cat files produced by
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.b man
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will be compressed with
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.ip
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.b "gzip \-7c"
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.lp
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and have a
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.b .gz
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extension appended.
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If
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.b gzip
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is not found,
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.ip
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.b "compress \-c"
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.lp
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is used as the compressor and the extension
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.b .Z
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is appended.
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.lp
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To store cat files in an uncompressed state and to disable compressed
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extension processing completely, edit
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.i config.h
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and comment out the following line
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.lp
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#define COMP_CAT 1
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.lp
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.BS 3 "Stray cats"
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.lp
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Normally,
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.b man
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will only look for cat files with the default compression extension.
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The default compression extension is dependent on the default compressor
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and may be an empty string if the support for compressed cats is disabled.
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.lp
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It is possible for a system to be supplied with stray cat files located in the
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traditional cat page hierarchy.
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To make matters worse, they may have
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compression extensions other than the default and reside on read-only media.
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In such circumstances, stray cat files will be accepted with any compression
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extension that is also supported for manual pages.
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.lp
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This special treatment of stray cat pages is removed if
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support for compressed manual pages is turned off or not available.
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