lbrate(1) Archive Extraction lbrate(1)NAMElbrate - extract/decompress CP/M LBR archives
SYNOPSISlbrate [-chlntv] [archive.lbr] [match1 [match2 ... ]]
DESCRIPTIONlbrate lists, extracts, or tests CP/M LBR archives. It does this in an
`unzip'-like manner, mostly hiding the details of individually com‐
pressed and renamed files, and transparently deals with the required
decompression and renaming.
(It can also work on CP/M-ish compressed files (`squeezed', etc.) out‐
side of such archives, treating them as if they were really single-mem‐
ber LBRs.)
The default action is to extract all files in the specified archive;
see OPTIONS below for how to do other things instead.
OPTIONS-c use/show creation date (and time) rather than last-modified.
(But note that many LBRs lack date/time stamps entirely.)
-h give terse usage help.
-l list files in archive. If verbose listings are enabled, it shows
the filename (and the modified filename actually given in the
LBR, if the file is compressed), compression method, compressed
size (the uncompressed size can't be easily determined), and
CRC; but by default, it just shows the filename and compressed
size.
-n don't decompress files, just extract the files precisely as they
are stored in the LBR. This also means the possibly-modified LBR
filenames are used (see FILENAME ISSUES below), even when used
with `-l'.
-t test files in archive - check file CRCs at the LBR level, also
checking file checksums for any compressed files. (If used
together with `-n', only LBR CRCs are checked.)
-v give verbose output (when used with `-l'). Using `-lv' is the
easiest way to see the filenames specified in the LBR, which are
(due to compression/renaming) usually not the original file‐
names.
archive.lbr
the archive to operate on. You can also specify a CP/M-ish indi‐
vidually-compressed file (these have names like `foo.tqt',
`bar.dzc', and `baz.cym'); these are treated as if they were
single-entry LBRs.
match1 etc.
optionally specify which archive members to list/extract/test.
Those which match any of these filenames/wildcards are pro‐
cessed. Wildcard operators supported are shell-like `*' and `?',
but don't forget to quote arguments which use these (e.g.
`lbrate foo.lbr '*.bar''). Note that, unless you're using `-n',
these matches are always on the original filename (the one
lbrate normally shows you), and not the (often modified) file‐
name stored in the LBR.
FILENAME ISSUES
All this talk of modified filenames is probably rather confusing, so
here's a brief summary of what the deal is with LBR files for those
unfamiliar with the situation.
The LBR format in itself is a pure, uncompressed archival format; a bit
like tar files. But while tar files are normally compressed after the
component files get bundled together, LBR files normally bundle
together compressed files.
Now, CP/M is limited to 8.3 file naming, so compressed files weren't
indicated by adding an extension, but (loosely speaking) by changing
the 2nd character of the extension. So foo.txt becomes foo.tqt, for
example. What happens to the original name? Easy, it gets stored in the
compressed file, and is restored when it's decompressed.
So, there we have the justification for lbrate's behaviour - LBRs are
often full of weirdly-named files, so it's generally best to peek into
the start of any compressed files, find the real filename, and use
that. Since the compressed file formats all have `magic numbers' and
can be very reliably detected, this approach is pretty much ideal.
EXTRACTING MULTIPLE ARCHIVESlbrate follows the `unzip'-like practice of working on only one archive
per run, with further `filenames' given on the command-line actually
specifying files to extract (or whatever). The easiest way to work on
multiple files with lbrate is simply to run it multiple times using
for; for example:
for i in *.{lbr,LBR}; do lbrate-t $i; done
The above would test all LBR archives in the current directory.
Another example, this time to extract all the squeezed/crunched files:
for i in *.?[qzQZ]*; do lbrate $i; done
TIMESTAMPS
While the LBR format did support file dates/times, there are a lot of
LBRs which lack them. lbrate's approach to this is simply to use them
whenever available. The last-modified date/time is used/shown by
default; specify `-c' to get creation date/time instead.
DIAGNOSTICS
Given the two-level nature of the extraction process (the raw extrac‐
tion of the file from the LBR, then any required decompression), there
are (unless `-n' is used) two different ways that a corrupted archive
can cause reading from the LBR to fail. lbrate tries to communicate
this in the way which seems most reasonable given the way it's being
run, as described here.
When testing an archive, lbrate gives priority to LBR CRC errors. It
only mentions an error decompressing when there wasn't a CRC error at
the LBR level.
When extracting an archive, lbrate considers decompression errors more
important; and note that currently, a decompression error means no file
data is written. (Though in this case it does say `seems valid at LBR
level?' if the LBR CRC was ok.) If there's `only' an LBR CRC mismatch,
then file data is written, but with a warning.
BUGS
The CRC used by LBR is only 16-bit, so `-t' is a less-than-perfect
test. The additional checksum test for compressed files may improve
matters slightly.
SEE ALSOnomarch(1), tar(1), gzip(1), bzip2(1)
The CP/M programs `lt' and `lbrext' do something similar.
AUTHOR
Russell Marks (rus@svgalib.org).
The LZH decompression is based on code by Haruhiko Okumura, Haruyasu
Yoshizaki, and Kenji Rikitake.
Version 1.1 30th November, 2001 lbrate(1)
