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grep branch, master, updated. v3.6-16-gb216515
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From: |
Paul Eggert |
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Subject: |
grep branch, master, updated. v3.6-16-gb216515 |
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Date: |
Fri, 1 Jan 2021 22:00:13 -0500 (EST) |
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http://git.savannah.gnu.org/cgit/grep.git/commit/?id=b216515f9c72dd7529e3e587abed101efd1d9ae5
commit b216515f9c72dd7529e3e587abed101efd1d9ae5
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri Jan 1 18:27:07 2021 -0800
doc: further clarify regexp structure
* doc/grep.texi (Fundamental Structure)
(Back-references and Subexpressions, Basic vs Extended):
Further clarifications.
diff --git a/doc/grep.texi b/doc/grep.texi
index 630a7d7..19099cc 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -1204,12 +1204,12 @@ pages, but work only if PCRE is available in the system.
@node Fundamental Structure
@section Fundamental Structure
-The fundamental building blocks are the regular expressions that match
-a single character.
-Most characters, including all letters and digits,
-are regular expressions that match themselves.
-The special characters @samp{.?*+@{|()[\^$}, unless quoted by being
-preceded by a backslash, have the following uses.
+@cindex ordinary characters
+@cindex special characters
+In regular expressions, the characters @samp{.?*+@{|()[\^$} are
+@dfn{special characters} and have uses described below. All other
+characters are @dfn{ordinary characters}, and each ordinary character
+is a regular expression that matches itself.
@opindex .
@cindex dot
@@ -1516,14 +1516,17 @@ to beginning or end of a line, respectively.
@cindex subexpression
@cindex back-reference
-The back-reference @samp{\@var{n}}, where @var{n} is a single digit, matches
+The back-reference @samp{\@var{n}},
+where @var{n} is a single nonzero digit, matches
the substring previously matched by the @var{n}th parenthesized subexpression
of the regular expression.
For example, @samp{(a)\1} matches @samp{aa}.
-When used with alternation, if the group does not participate in the match then
-the back-reference makes the whole match fail.
-For example, @samp{a(.)|b\1}
-will not match @samp{ba}.
+If the parenthesized subexpression does not participate in the match,
+the back-reference makes the whole match fail;
+for example, @samp{(a)*\1} fails to match @samp{a}.
+If the parenthesized subexpression matches more than one substring,
+the back-reference refers to the last matched substring;
+for example, @samp{^(ab*)*\1$} matches @samp{ababbabb} but not @samp{ababbab}.
When multiple regular expressions are given with
@option{-e} or from a file (@samp{-f @var{file}}),
back-references are local to each expression.
@@ -1534,17 +1537,43 @@ back-references are local to each expression.
@section Basic vs Extended Regular Expressions
@cindex basic regular expressions
-In basic regular expressions the special characters @samp{?}, @samp{+},
+In basic regular expressions the characters @samp{?}, @samp{+},
@samp{@{}, @samp{|}, @samp{(}, and @samp{)} lose their special meaning;
instead use the backslashed versions @samp{\?}, @samp{\+}, @samp{\@{},
@samp{\|}, @samp{\(}, and @samp{\)}. Also, a backslash is needed
-before an interval expression's closing @samp{@}}.
+before an interval expression's closing @samp{@}}, and an unmatched
+@code{\)} is invalid.
+
+Portable scripts should avoid the following constructs, as
+POSIX says they produce undefined results:
+
+@itemize @bullet
+@item
+Extended regular expressions that use back-references.
+@item
+Basic regular expressions that use @samp{\?}, @samp{\+}, or @samp{\|}.
+@item
+Empty parenthesized regular expressions like @samp{()}.
+@item
+Empty alternatives (as in, e.g, @samp{a|}).
+@item
+Repetition operators that immediately follow empty expressions,
+unescaped @samp{$}, or other repetition operators.
+@item
+A backslash escaping an ordinary character (e.g., @samp{\S}),
+unless it is a back-reference.
+@item
+An unescaped @samp{[} that is not part of a bracket expression.
+@item
+In extended regular expressions, an unescaped @samp{@{} that is not
+part of an interval expression.
+@end itemize
@cindex interval expressions
Traditional @command{egrep} did not support interval expressions and
some @command{egrep} implementations use @samp{\@{} and @samp{\@}} instead, so
-portable scripts should avoid @samp{@{} in @samp{grep@ -E} patterns and
-should use @samp{[@{]} to match a literal @samp{@{}.
+portable scripts should avoid interval expressions in @samp{grep@ -E} patterns
+and should use @samp{[@{]} to match a literal @samp{@{}.
GNU @command{grep@ -E} attempts to support traditional usage by
assuming that @samp{@{} is not special if it would be the start of an
@@ -1865,11 +1894,8 @@ Why is this back-reference failing?
echo 'ba' | grep -E '(a)\1|b\1'
@end example
-This gives no output, because the first alternate @samp{(a)\1} does not match,
-as there is no @samp{aa} in the input, so the @samp{\1} in the second alternate
+This outputs an error message, because the second @samp{\1}
has nothing to refer back to, meaning it will never match anything.
-(The second alternate in this example can only match
-if the first alternate has matched---making the second one superfluous.)
@item
How can I match across lines?
http://git.savannah.gnu.org/cgit/grep.git/commit/?id=6b454dc20d5ce5d3a05cc0208893038fb9485cd7
commit b216515f9c72dd7529e3e587abed101efd1d9ae5
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri Jan 1 18:27:07 2021 -0800
doc: further clarify regexp structure
* doc/grep.texi (Fundamental Structure)
(Back-references and Subexpressions, Basic vs Extended):
Further clarifications.
diff --git a/doc/grep.texi b/doc/grep.texi
index 630a7d7..19099cc 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -1204,12 +1204,12 @@ pages, but work only if PCRE is available in the system.
@node Fundamental Structure
@section Fundamental Structure
-The fundamental building blocks are the regular expressions that match
-a single character.
-Most characters, including all letters and digits,
-are regular expressions that match themselves.
-The special characters @samp{.?*+@{|()[\^$}, unless quoted by being
-preceded by a backslash, have the following uses.
+@cindex ordinary characters
+@cindex special characters
+In regular expressions, the characters @samp{.?*+@{|()[\^$} are
+@dfn{special characters} and have uses described below. All other
+characters are @dfn{ordinary characters}, and each ordinary character
+is a regular expression that matches itself.
@opindex .
@cindex dot
@@ -1516,14 +1516,17 @@ to beginning or end of a line, respectively.
@cindex subexpression
@cindex back-reference
-The back-reference @samp{\@var{n}}, where @var{n} is a single digit, matches
+The back-reference @samp{\@var{n}},
+where @var{n} is a single nonzero digit, matches
the substring previously matched by the @var{n}th parenthesized subexpression
of the regular expression.
For example, @samp{(a)\1} matches @samp{aa}.
-When used with alternation, if the group does not participate in the match then
-the back-reference makes the whole match fail.
-For example, @samp{a(.)|b\1}
-will not match @samp{ba}.
+If the parenthesized subexpression does not participate in the match,
+the back-reference makes the whole match fail;
+for example, @samp{(a)*\1} fails to match @samp{a}.
+If the parenthesized subexpression matches more than one substring,
+the back-reference refers to the last matched substring;
+for example, @samp{^(ab*)*\1$} matches @samp{ababbabb} but not @samp{ababbab}.
When multiple regular expressions are given with
@option{-e} or from a file (@samp{-f @var{file}}),
back-references are local to each expression.
@@ -1534,17 +1537,43 @@ back-references are local to each expression.
@section Basic vs Extended Regular Expressions
@cindex basic regular expressions
-In basic regular expressions the special characters @samp{?}, @samp{+},
+In basic regular expressions the characters @samp{?}, @samp{+},
@samp{@{}, @samp{|}, @samp{(}, and @samp{)} lose their special meaning;
instead use the backslashed versions @samp{\?}, @samp{\+}, @samp{\@{},
@samp{\|}, @samp{\(}, and @samp{\)}. Also, a backslash is needed
-before an interval expression's closing @samp{@}}.
+before an interval expression's closing @samp{@}}, and an unmatched
+@code{\)} is invalid.
+
+Portable scripts should avoid the following constructs, as
+POSIX says they produce undefined results:
+
+@itemize @bullet
+@item
+Extended regular expressions that use back-references.
+@item
+Basic regular expressions that use @samp{\?}, @samp{\+}, or @samp{\|}.
+@item
+Empty parenthesized regular expressions like @samp{()}.
+@item
+Empty alternatives (as in, e.g, @samp{a|}).
+@item
+Repetition operators that immediately follow empty expressions,
+unescaped @samp{$}, or other repetition operators.
+@item
+A backslash escaping an ordinary character (e.g., @samp{\S}),
+unless it is a back-reference.
+@item
+An unescaped @samp{[} that is not part of a bracket expression.
+@item
+In extended regular expressions, an unescaped @samp{@{} that is not
+part of an interval expression.
+@end itemize
@cindex interval expressions
Traditional @command{egrep} did not support interval expressions and
some @command{egrep} implementations use @samp{\@{} and @samp{\@}} instead, so
-portable scripts should avoid @samp{@{} in @samp{grep@ -E} patterns and
-should use @samp{[@{]} to match a literal @samp{@{}.
+portable scripts should avoid interval expressions in @samp{grep@ -E} patterns
+and should use @samp{[@{]} to match a literal @samp{@{}.
GNU @command{grep@ -E} attempts to support traditional usage by
assuming that @samp{@{} is not special if it would be the start of an
@@ -1865,11 +1894,8 @@ Why is this back-reference failing?
echo 'ba' | grep -E '(a)\1|b\1'
@end example
-This gives no output, because the first alternate @samp{(a)\1} does not match,
-as there is no @samp{aa} in the input, so the @samp{\1} in the second alternate
+This outputs an error message, because the second @samp{\1}
has nothing to refer back to, meaning it will never match anything.
-(The second alternate in this example can only match
-if the first alternate has matched---making the second one superfluous.)
@item
How can I match across lines?
http://git.savannah.gnu.org/cgit/grep.git/commit/?id=bcf26593451cd9b82724934ea9abb04a1dffc3b1
commit b216515f9c72dd7529e3e587abed101efd1d9ae5
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri Jan 1 18:27:07 2021 -0800
doc: further clarify regexp structure
* doc/grep.texi (Fundamental Structure)
(Back-references and Subexpressions, Basic vs Extended):
Further clarifications.
diff --git a/doc/grep.texi b/doc/grep.texi
index 630a7d7..19099cc 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -1204,12 +1204,12 @@ pages, but work only if PCRE is available in the system.
@node Fundamental Structure
@section Fundamental Structure
-The fundamental building blocks are the regular expressions that match
-a single character.
-Most characters, including all letters and digits,
-are regular expressions that match themselves.
-The special characters @samp{.?*+@{|()[\^$}, unless quoted by being
-preceded by a backslash, have the following uses.
+@cindex ordinary characters
+@cindex special characters
+In regular expressions, the characters @samp{.?*+@{|()[\^$} are
+@dfn{special characters} and have uses described below. All other
+characters are @dfn{ordinary characters}, and each ordinary character
+is a regular expression that matches itself.
@opindex .
@cindex dot
@@ -1516,14 +1516,17 @@ to beginning or end of a line, respectively.
@cindex subexpression
@cindex back-reference
-The back-reference @samp{\@var{n}}, where @var{n} is a single digit, matches
+The back-reference @samp{\@var{n}},
+where @var{n} is a single nonzero digit, matches
the substring previously matched by the @var{n}th parenthesized subexpression
of the regular expression.
For example, @samp{(a)\1} matches @samp{aa}.
-When used with alternation, if the group does not participate in the match then
-the back-reference makes the whole match fail.
-For example, @samp{a(.)|b\1}
-will not match @samp{ba}.
+If the parenthesized subexpression does not participate in the match,
+the back-reference makes the whole match fail;
+for example, @samp{(a)*\1} fails to match @samp{a}.
+If the parenthesized subexpression matches more than one substring,
+the back-reference refers to the last matched substring;
+for example, @samp{^(ab*)*\1$} matches @samp{ababbabb} but not @samp{ababbab}.
When multiple regular expressions are given with
@option{-e} or from a file (@samp{-f @var{file}}),
back-references are local to each expression.
@@ -1534,17 +1537,43 @@ back-references are local to each expression.
@section Basic vs Extended Regular Expressions
@cindex basic regular expressions
-In basic regular expressions the special characters @samp{?}, @samp{+},
+In basic regular expressions the characters @samp{?}, @samp{+},
@samp{@{}, @samp{|}, @samp{(}, and @samp{)} lose their special meaning;
instead use the backslashed versions @samp{\?}, @samp{\+}, @samp{\@{},
@samp{\|}, @samp{\(}, and @samp{\)}. Also, a backslash is needed
-before an interval expression's closing @samp{@}}.
+before an interval expression's closing @samp{@}}, and an unmatched
+@code{\)} is invalid.
+
+Portable scripts should avoid the following constructs, as
+POSIX says they produce undefined results:
+
+@itemize @bullet
+@item
+Extended regular expressions that use back-references.
+@item
+Basic regular expressions that use @samp{\?}, @samp{\+}, or @samp{\|}.
+@item
+Empty parenthesized regular expressions like @samp{()}.
+@item
+Empty alternatives (as in, e.g, @samp{a|}).
+@item
+Repetition operators that immediately follow empty expressions,
+unescaped @samp{$}, or other repetition operators.
+@item
+A backslash escaping an ordinary character (e.g., @samp{\S}),
+unless it is a back-reference.
+@item
+An unescaped @samp{[} that is not part of a bracket expression.
+@item
+In extended regular expressions, an unescaped @samp{@{} that is not
+part of an interval expression.
+@end itemize
@cindex interval expressions
Traditional @command{egrep} did not support interval expressions and
some @command{egrep} implementations use @samp{\@{} and @samp{\@}} instead, so
-portable scripts should avoid @samp{@{} in @samp{grep@ -E} patterns and
-should use @samp{[@{]} to match a literal @samp{@{}.
+portable scripts should avoid interval expressions in @samp{grep@ -E} patterns
+and should use @samp{[@{]} to match a literal @samp{@{}.
GNU @command{grep@ -E} attempts to support traditional usage by
assuming that @samp{@{} is not special if it would be the start of an
@@ -1865,11 +1894,8 @@ Why is this back-reference failing?
echo 'ba' | grep -E '(a)\1|b\1'
@end example
-This gives no output, because the first alternate @samp{(a)\1} does not match,
-as there is no @samp{aa} in the input, so the @samp{\1} in the second alternate
+This outputs an error message, because the second @samp{\1}
has nothing to refer back to, meaning it will never match anything.
-(The second alternate in this example can only match
-if the first alternate has matched---making the second one superfluous.)
@item
How can I match across lines?
http://git.savannah.gnu.org/cgit/grep.git/commit/?id=e84a2ea9d2fb820d0af60f9632f869bcd5edd93a
commit b216515f9c72dd7529e3e587abed101efd1d9ae5
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri Jan 1 18:27:07 2021 -0800
doc: further clarify regexp structure
* doc/grep.texi (Fundamental Structure)
(Back-references and Subexpressions, Basic vs Extended):
Further clarifications.
diff --git a/doc/grep.texi b/doc/grep.texi
index 630a7d7..19099cc 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -1204,12 +1204,12 @@ pages, but work only if PCRE is available in the system.
@node Fundamental Structure
@section Fundamental Structure
-The fundamental building blocks are the regular expressions that match
-a single character.
-Most characters, including all letters and digits,
-are regular expressions that match themselves.
-The special characters @samp{.?*+@{|()[\^$}, unless quoted by being
-preceded by a backslash, have the following uses.
+@cindex ordinary characters
+@cindex special characters
+In regular expressions, the characters @samp{.?*+@{|()[\^$} are
+@dfn{special characters} and have uses described below. All other
+characters are @dfn{ordinary characters}, and each ordinary character
+is a regular expression that matches itself.
@opindex .
@cindex dot
@@ -1516,14 +1516,17 @@ to beginning or end of a line, respectively.
@cindex subexpression
@cindex back-reference
-The back-reference @samp{\@var{n}}, where @var{n} is a single digit, matches
+The back-reference @samp{\@var{n}},
+where @var{n} is a single nonzero digit, matches
the substring previously matched by the @var{n}th parenthesized subexpression
of the regular expression.
For example, @samp{(a)\1} matches @samp{aa}.
-When used with alternation, if the group does not participate in the match then
-the back-reference makes the whole match fail.
-For example, @samp{a(.)|b\1}
-will not match @samp{ba}.
+If the parenthesized subexpression does not participate in the match,
+the back-reference makes the whole match fail;
+for example, @samp{(a)*\1} fails to match @samp{a}.
+If the parenthesized subexpression matches more than one substring,
+the back-reference refers to the last matched substring;
+for example, @samp{^(ab*)*\1$} matches @samp{ababbabb} but not @samp{ababbab}.
When multiple regular expressions are given with
@option{-e} or from a file (@samp{-f @var{file}}),
back-references are local to each expression.
@@ -1534,17 +1537,43 @@ back-references are local to each expression.
@section Basic vs Extended Regular Expressions
@cindex basic regular expressions
-In basic regular expressions the special characters @samp{?}, @samp{+},
+In basic regular expressions the characters @samp{?}, @samp{+},
@samp{@{}, @samp{|}, @samp{(}, and @samp{)} lose their special meaning;
instead use the backslashed versions @samp{\?}, @samp{\+}, @samp{\@{},
@samp{\|}, @samp{\(}, and @samp{\)}. Also, a backslash is needed
-before an interval expression's closing @samp{@}}.
+before an interval expression's closing @samp{@}}, and an unmatched
+@code{\)} is invalid.
+
+Portable scripts should avoid the following constructs, as
+POSIX says they produce undefined results:
+
+@itemize @bullet
+@item
+Extended regular expressions that use back-references.
+@item
+Basic regular expressions that use @samp{\?}, @samp{\+}, or @samp{\|}.
+@item
+Empty parenthesized regular expressions like @samp{()}.
+@item
+Empty alternatives (as in, e.g, @samp{a|}).
+@item
+Repetition operators that immediately follow empty expressions,
+unescaped @samp{$}, or other repetition operators.
+@item
+A backslash escaping an ordinary character (e.g., @samp{\S}),
+unless it is a back-reference.
+@item
+An unescaped @samp{[} that is not part of a bracket expression.
+@item
+In extended regular expressions, an unescaped @samp{@{} that is not
+part of an interval expression.
+@end itemize
@cindex interval expressions
Traditional @command{egrep} did not support interval expressions and
some @command{egrep} implementations use @samp{\@{} and @samp{\@}} instead, so
-portable scripts should avoid @samp{@{} in @samp{grep@ -E} patterns and
-should use @samp{[@{]} to match a literal @samp{@{}.
+portable scripts should avoid interval expressions in @samp{grep@ -E} patterns
+and should use @samp{[@{]} to match a literal @samp{@{}.
GNU @command{grep@ -E} attempts to support traditional usage by
assuming that @samp{@{} is not special if it would be the start of an
@@ -1865,11 +1894,8 @@ Why is this back-reference failing?
echo 'ba' | grep -E '(a)\1|b\1'
@end example
-This gives no output, because the first alternate @samp{(a)\1} does not match,
-as there is no @samp{aa} in the input, so the @samp{\1} in the second alternate
+This outputs an error message, because the second @samp{\1}
has nothing to refer back to, meaning it will never match anything.
-(The second alternate in this example can only match
-if the first alternate has matched---making the second one superfluous.)
@item
How can I match across lines?
http://git.savannah.gnu.org/cgit/grep.git/commit/?id=ebbb25f6ef8908ca4e9a6c8bb95a64eb2328a4d9
commit b216515f9c72dd7529e3e587abed101efd1d9ae5
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri Jan 1 18:27:07 2021 -0800
doc: further clarify regexp structure
* doc/grep.texi (Fundamental Structure)
(Back-references and Subexpressions, Basic vs Extended):
Further clarifications.
diff --git a/doc/grep.texi b/doc/grep.texi
index 630a7d7..19099cc 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -1204,12 +1204,12 @@ pages, but work only if PCRE is available in the system.
@node Fundamental Structure
@section Fundamental Structure
-The fundamental building blocks are the regular expressions that match
-a single character.
-Most characters, including all letters and digits,
-are regular expressions that match themselves.
-The special characters @samp{.?*+@{|()[\^$}, unless quoted by being
-preceded by a backslash, have the following uses.
+@cindex ordinary characters
+@cindex special characters
+In regular expressions, the characters @samp{.?*+@{|()[\^$} are
+@dfn{special characters} and have uses described below. All other
+characters are @dfn{ordinary characters}, and each ordinary character
+is a regular expression that matches itself.
@opindex .
@cindex dot
@@ -1516,14 +1516,17 @@ to beginning or end of a line, respectively.
@cindex subexpression
@cindex back-reference
-The back-reference @samp{\@var{n}}, where @var{n} is a single digit, matches
+The back-reference @samp{\@var{n}},
+where @var{n} is a single nonzero digit, matches
the substring previously matched by the @var{n}th parenthesized subexpression
of the regular expression.
For example, @samp{(a)\1} matches @samp{aa}.
-When used with alternation, if the group does not participate in the match then
-the back-reference makes the whole match fail.
-For example, @samp{a(.)|b\1}
-will not match @samp{ba}.
+If the parenthesized subexpression does not participate in the match,
+the back-reference makes the whole match fail;
+for example, @samp{(a)*\1} fails to match @samp{a}.
+If the parenthesized subexpression matches more than one substring,
+the back-reference refers to the last matched substring;
+for example, @samp{^(ab*)*\1$} matches @samp{ababbabb} but not @samp{ababbab}.
When multiple regular expressions are given with
@option{-e} or from a file (@samp{-f @var{file}}),
back-references are local to each expression.
@@ -1534,17 +1537,43 @@ back-references are local to each expression.
@section Basic vs Extended Regular Expressions
@cindex basic regular expressions
-In basic regular expressions the special characters @samp{?}, @samp{+},
+In basic regular expressions the characters @samp{?}, @samp{+},
@samp{@{}, @samp{|}, @samp{(}, and @samp{)} lose their special meaning;
instead use the backslashed versions @samp{\?}, @samp{\+}, @samp{\@{},
@samp{\|}, @samp{\(}, and @samp{\)}. Also, a backslash is needed
-before an interval expression's closing @samp{@}}.
+before an interval expression's closing @samp{@}}, and an unmatched
+@code{\)} is invalid.
+
+Portable scripts should avoid the following constructs, as
+POSIX says they produce undefined results:
+
+@itemize @bullet
+@item
+Extended regular expressions that use back-references.
+@item
+Basic regular expressions that use @samp{\?}, @samp{\+}, or @samp{\|}.
+@item
+Empty parenthesized regular expressions like @samp{()}.
+@item
+Empty alternatives (as in, e.g, @samp{a|}).
+@item
+Repetition operators that immediately follow empty expressions,
+unescaped @samp{$}, or other repetition operators.
+@item
+A backslash escaping an ordinary character (e.g., @samp{\S}),
+unless it is a back-reference.
+@item
+An unescaped @samp{[} that is not part of a bracket expression.
+@item
+In extended regular expressions, an unescaped @samp{@{} that is not
+part of an interval expression.
+@end itemize
@cindex interval expressions
Traditional @command{egrep} did not support interval expressions and
some @command{egrep} implementations use @samp{\@{} and @samp{\@}} instead, so
-portable scripts should avoid @samp{@{} in @samp{grep@ -E} patterns and
-should use @samp{[@{]} to match a literal @samp{@{}.
+portable scripts should avoid interval expressions in @samp{grep@ -E} patterns
+and should use @samp{[@{]} to match a literal @samp{@{}.
GNU @command{grep@ -E} attempts to support traditional usage by
assuming that @samp{@{} is not special if it would be the start of an
@@ -1865,11 +1894,8 @@ Why is this back-reference failing?
echo 'ba' | grep -E '(a)\1|b\1'
@end example
-This gives no output, because the first alternate @samp{(a)\1} does not match,
-as there is no @samp{aa} in the input, so the @samp{\1} in the second alternate
+This outputs an error message, because the second @samp{\1}
has nothing to refer back to, meaning it will never match anything.
-(The second alternate in this example can only match
-if the first alternate has matched---making the second one superfluous.)
@item
How can I match across lines?
-----------------------------------------------------------------------
Summary of changes:
AUTHORS | 2 +-
ChangeLog-2009 | 2 +-
HACKING | 2 +-
Makefile.am | 2 +-
NEWS | 2 +-
README | 2 +-
README-alpha | 2 +-
README-hacking | 2 +-
TODO | 2 +-
bootstrap | 22 ++++++++--
bootstrap.conf | 2 +-
cfg.mk | 2 +-
configure.ac | 2 +-
doc/Makefile.am | 2 +-
doc/grep.in.1 | 2 +-
doc/grep.texi | 68 +++++++++++++++++++++---------
gnulib | 2 +-
lib/Makefile.am | 2 +-
lib/colorize-posix.c | 2 +-
lib/colorize-w32.c | 2 +-
lib/colorize.h | 2 +-
m4/pcre.m4 | 2 +-
po/POTFILES.in | 2 +-
src/Makefile.am | 2 +-
src/dfasearch.c | 2 +-
src/die.h | 2 +-
src/grep.c | 2 +-
src/grep.h | 2 +-
src/kwsearch.c | 2 +-
src/kwset.c | 2 +-
src/kwset.h | 2 +-
src/pcresearch.c | 2 +-
src/search.h | 2 +-
src/searchutils.c | 2 +-
src/system.h | 2 +-
tests/Coreutils.pm | 2 +-
tests/CuSkip.pm | 2 +-
tests/CuTmpdir.pm | 2 +-
tests/Makefile.am | 2 +-
tests/backref | 2 +-
tests/backref-alt | 2 +-
tests/backslash-dot | 2 +-
tests/backslash-s-and-repetition-operators | 2 +-
tests/backslash-s-vs-invalid-multibyte | 2 +-
tests/binary-file-matches | 2 +-
tests/bre | 2 +-
tests/bre.awk | 2 +-
tests/c-locale | 2 +-
tests/case-fold-titlecase | 2 +-
tests/count-newline | 2 +-
tests/dfa-coverage | 2 +-
tests/dfa-heap-overrun | 2 +-
tests/dfa-invalid-utf8 | 2 +-
tests/empty | 2 +-
tests/empty-line-mb | 2 +-
tests/encoding-error | 2 +-
tests/envvar-check | 2 +-
tests/ere | 2 +-
tests/ere.awk | 2 +-
tests/false-match-mb-non-utf8 | 2 +-
tests/fgrep-longest | 2 +-
tests/file | 2 +-
tests/filename-lineno.pl | 2 +-
tests/fmbtest | 2 +-
tests/foad1 | 2 +-
tests/get-mb-cur-max.c | 2 +-
tests/hash-collision-perf | 2 +-
tests/help-version | 2 +-
tests/high-bit-range | 2 +-
tests/init.sh | 4 +-
tests/initial-tab | 2 +-
tests/khadafy | 2 +-
tests/kwset-abuse | 2 +-
tests/long-pattern-perf | 2 +-
tests/many-regex-performance | 2 +-
tests/match-lines | 2 +-
tests/mb-dot-newline | 2 +-
tests/mb-non-UTF8-overrun | 2 +-
tests/mb-non-UTF8-perf-Fw | 2 +-
tests/mb-non-UTF8-performance | 2 +-
tests/mb-non-UTF8-word-boundary | 2 +-
tests/multibyte-white-space | 2 +-
tests/multiple-begin-or-end-line | 2 +-
tests/null-byte | 2 +-
tests/options | 2 +-
tests/pcre | 2 +-
tests/pcre-abort | 2 +-
tests/pcre-count | 2 +-
tests/pcre-infloop | 2 +-
tests/pcre-invalid-utf8-infloop | 2 +-
tests/pcre-invalid-utf8-input | 2 +-
tests/pcre-jitstack | 2 +-
tests/pcre-o | 2 +-
tests/pcre-utf8 | 2 +-
tests/pcre-w | 2 +-
tests/pcre-wx-backref | 2 +-
tests/posix-bracket | 2 +-
tests/proc | 2 +-
tests/spencer1 | 2 +-
tests/spencer1-locale | 2 +-
tests/spencer1-locale.awk | 2 +-
tests/spencer1.awk | 2 +-
tests/spencer2 | 2 +-
tests/status | 2 +-
tests/surrogate-pair | 2 +-
tests/symlink | 2 +-
tests/tests | 2 +-
tests/triple-backref | 2 +-
tests/turkish-I | 2 +-
tests/turkish-I-without-dot | 2 +-
tests/turkish-eyes | 2 +-
tests/two-chars | 2 +-
tests/two-files | 2 +-
tests/unibyte-binary | 2 +-
tests/unibyte-bracket-expr | 2 +-
tests/unibyte-negated-circumflex | 2 +-
tests/utf8-bracket | 2 +-
tests/write-error-msg | 2 +-
tests/yesno | 2 +-
tests/z-anchor-newline | 2 +-
120 files changed, 184 insertions(+), 144 deletions(-)
hooks/post-receive
--
grep
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