Use "read" instead of "awk" in xzless to get the version
number of "less". The need for awk was introduced in
the commit db5c1817fa.
Thanks to Ariel P for the patch.
In v4.999.9beta~30 (xzless: Support compressed standard input,
2009-08-09), xzless learned to parse ‘less -V’ output to figure out
whether less is new enough to handle $LESSOPEN settings starting
with “|-”. That worked well for a while, but the version string from
‘less’ versions 448 (June, 2012) is misparsed, producing a warning:
$ xzless /tmp/test.xz; echo $?
/usr/bin/xzless: line 49: test: 456 (GNU regular expressions): \
integer expression expected
0
More precisely, modern ‘less’ lists the regexp implementation along
with its version number, and xzless passes the entire version number
with attached parenthetical phrase as a number to "test $a -gt $b",
producing the above confusing message.
$ less-444 -V | head -1
less 444
$ less -V | head -1
less 456 (no regular expressions)
So relax the pattern matched --- instead of expecting "less <number>",
look for a line of the form "less <number>[ (extra parenthetical)]".
While at it, improve the behavior when no matching line is found ---
instead of producing a cryptic message, we can fall back on a LESSPIPE
setting that is supported by all versions of ‘less’.
The implementation uses "awk" for simplicity. Hopefully that’s
portable enough.
Reported-by: Jörg-Volker Peetz <jvpeetz@web.de>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
It can be somewhat confusing that
less < some_file.txt
works fine, whereas
xzless < some_file.txt.xz
does not. Since version 429, ‘less’ allows a filter specified in
the LESSOPEN environment variable to preprocess its input even if
it comes from standard input, if $LESSOPEN begins with ‘|-’. So
set $LESSOPEN to take advantage of this feature.
Check less’s version at runtime so xzless can continue to work
with older versions.
the latest versions found from gzip CVS repository.
configure will try to find a POSIX shell to be used by
the scripts. This should ease portability on systems
which have pre-POSIX /bin/sh.
xzgrep and xzdiff support .xz, .lzma, .gz, and .bz2 files.
xzmore and xzless support only .xz and .lzma files.
The name of the xz executable used in these scripts is
now correct even if --program-transform-name has been used.
Lasse Collin
Jonathan Nieder