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* doc/autoconf.texi (Particular Programs): Do not promise that

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we always prefer the GNU version of the program, and that we
search according to PATH; both rules can have exceptions.
Update description of AC_PROG_GREP, AC_PROG_EGREP, AC_PROG_FGREP,
AC_PROG_SED.  Move descriptions of limitations
to the Limitations of Usual Tools section.
(Limitations of Usual Tools) <sed>: Mention script length
limitations with Solaris /usr/ucb/sed.
<grep>: Fix wording for empty alternative.  Mention that -c and
-l should not be combined, and that -E and -F should not be
combined.
This commit is contained in:
Paul Eggert 2006-05-22 17:27:50 +00:00
parent 49bb58f8f6
commit 7298fd6c1f
2 changed files with 46 additions and 24 deletions
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16
ChangeLog
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@ -1,3 +1,19 @@
2006-05-22 Paul Eggert <eggert@cs.ucla.edu>,
Ralf Wildenhues <Ralf.Wildenhues@gmx.de>,
Stepan Kasal <kasal@ucw.cz>
* doc/autoconf.texi (Particular Programs): Do not promise that
we always prefer the GNU version of the program, and that we
search according to PATH; both rules can have exceptions.
Update description of AC_PROG_GREP, AC_PROG_EGREP, AC_PROG_FGREP,
AC_PROG_SED. Move descriptions of limitations
to the Limitations of Usual Tools section.
(Limitations of Usual Tools) <sed>: Mention script length
limitations with Solaris /usr/ucb/sed.
<grep>: Fix wording for empty alternative. Mention that -c and
-l should not be combined, and that -E and -F should not be
combined.
2006-05-21 Paul Eggert <eggert@cs.ucla.edu>
and Ralf Wildenhues <Ralf.Wildenhues@gmx.de>

54
doc/autoconf.texi
View File

@ -3458,32 +3458,27 @@ best implementation.
@defmac AC_PROG_GREP
@acindex{PROG_GREP}
@ovindex GREP
On AIX the default @code{grep} silently truncates long lines on the
input before matching. On Solaris, @code{/usr/bin/grep} does not
understand the @option{-e} option. On NeXT, @code{grep} understands only a
single @option{-e} option. This macro looks for @sc{gnu} Grep or
else the best available @code{grep} or @code{ggrep} in the user's
@env{PATH} which accepts the longest input lines possible, and which
accepts and respects multiple @option{-e} options. Set the
output variable @code{GREP} to whatever is chosen.
Look for the best available @code{grep} or @code{ggrep} that accepts the
longest input lines possible, and that supports multiple @option{-e} options.
Set the output variable @code{GREP} to whatever is chosen.
@xref{Limitations of Usual Tools}, for more information about
portability problems with the @command{grep} command family.
@end defmac
@defmac AC_PROG_EGREP
@acindex{PROG_EGREP}
@ovindex EGREP
Check whether @code{$GREP -E} works, or else search the user's
@env{PATH} for @code{egrep}, and @code{gegrep}, in that order, and set
output variable @code{EGREP} to the one that accepts the longest input
lines.
Check whether @code{$GREP -E} works, or else look for the best available
@code{egrep} or @code{gegrep} that accepts the longest input lines possible.
Set the output variable @code{EGREP} to whatever is chosen.
@end defmac
@defmac AC_PROG_FGREP
@acindex{PROG_FGREP}
@ovindex FGREP
Check whether @code{$GREP -F} works, or else search the user's
@env{PATH} for @code{fgrep}, and @code{gfgrep}, in that order, and set
output variable @code{FGREP} to the one that accepts the longest input
lines.
Check whether @code{$GREP -F} works, or else look for the best available
@code{fgrep} or @code{gfgrep} that accepts the longest input lines possible.
Set the output variable @code{FGREP} to whatever is chosen.
@end defmac
@defmac AC_PROG_INSTALL
@ -3632,9 +3627,10 @@ is found, and otherwise to @samp{:} (do nothing).
@defmac AC_PROG_SED
@acindex{PROG_SED}
@ovindex SED
Set output variable @code{SED} to a Sed implementation on @env{PATH} that
truncates as few characters as possible. If @sc{gnu} Sed is found,
use that instead.
Set output variable @code{SED} to a Sed implementation that conforms to
Posix and does not have arbitrary length limits. Report an error if no
acceptable Sed is found. @xref{Limitations of Usual Tools}, for more
information about portability problems with Sed.
@end defmac
@defmac AC_PROG_YACC
@ -12778,7 +12774,7 @@ Portable extended regular expressions should use @samp{\} only to escape
characters in the string @samp{$()*+.?[\^@{|}. For example, @samp{\@}}
is not portable, even though it typically matches @samp{@}}.
The empty alternative is not portable, use @samp{?} instead. For
The empty alternative is not portable. Use @samp{?} instead. For
instance with Digital Unix v5.0:
@example
@ -12954,7 +12950,9 @@ while @acronym{GNU} @command{find} reports @samp{./foo-./foo}.
Portable scripts can rely on the @command{grep} options @option{-c},
@option{-l}, @option{-n}, and @option{-v}, but should avoid other
options. For example, don't use @option{-w}, as Posix does not require
it and Irix 6.5.16m's @command{grep} does not support it.
it and Irix 6.5.16m's @command{grep} does not support it. Also,
portable scripts should not combine @option{-c} with @option{-l},
as Posix does not allow this.
Some of the options required by Posix are not portable in practice.
Don't use @samp{grep -q} to suppress output, because many @command{grep}
@ -12968,9 +12966,12 @@ doesn't exist) of @code{grep} to @file{/dev/null}. Check the exit
status of @code{grep} to determine whether it found a match.
Some traditional @command{grep} implementations do not work on long
input lines. Also, many implementations do not support multiple regexps
input lines. On AIX the default @code{grep} silently truncates long
lines on the input before matching.
Also, many implementations do not support multiple regexps
with @option{-e}: they either reject @option{-e} entirely (e.g., Solaris)
or honor only the last pattern (e.g., @acronym{IRIX} 6.5). To
or honor only the last pattern (e.g., @acronym{IRIX} 6.5 and NeXT). To
work around these problems, invoke @code{AC_PROG_GREP} and then use
@code{$GREP}.
@ -12989,7 +12990,10 @@ implementations and with Open@acronym{BSD} 3.8 @command{grep}.
Traditional @command{grep} implementations (e.g., Solaris) do not
support the @option{-E} or @option{-F} options. To work around these
problems, invoke @code{AC_PROG_EGREP} and then use @code{$EGREP}, and
similarly for @code{AC_PROG_FGREP} and @code{$FGREP}.
similarly for @code{AC_PROG_FGREP} and @code{$FGREP}. Even if you are
willing to require support for Posix @command{grep}, your script should
not use both @option{-E} and @option{-F}, since Posix does not allow
this combination.
Portable @command{grep} regular expressions should use @samp{\} only to
escape characters in the string @samp{$()*.0123456789[\^@{@}}. For example,
@ -13214,6 +13218,8 @@ should not contain comments. HP-UX sed has a limit of 99 commands
(not counting @samp{:} commands) and
48 labels, which can not be circumvented by using more than one script
file. It can execute up to 19 reads with the @samp{r} command per cycle.
Solaris @command{/usr/ucb/sed} rejects usages that exceed an limit of
about 6000 bytes for the internal representation of commands.
Avoid redundant @samp{;}, as some @command{sed} implementations, such as
Net@acronym{BSD} 1.4.2's, incorrectly try to interpret the second