GNU grep NEWS                                    -*- outline -*-

* Noteworthy changes in release 2.9 (2011-06-21) [stable]

** Bug fixes

  grep no longer clobbers heap for an ERE like '(^| )*( |$)'
  [bug introduced in grep-2.6]

  grep is faster on regular expressions that match multibyte characters
  in brackets (such as '[áéíóú]').

  echo c|grep '[c]' would fail for any c in 0x80..0xff, with a uni-byte
  encoding for which the byte-to-wide-char mapping is nontrivial.  For
  example, the ISO-88591 locales are not affected, but ru_RU.KOI8-R is.
  [bug introduced in grep-2.6]

  grep -P no longer aborts when PCRE's backtracking limit is exceeded
  Before, echo aaaaaaaaaaaaaab |grep -P '((a+)*)+$' would abort.  Now,
  it diagnoses the problem and exits with status 2.


* Noteworthy changes in release 2.8 (2011-05-13) [stable]

** Bug fixes

  echo c|grep '[c]' would fail for any c in 0x80..0xff, and in many locales.
  E.g., printf '\xff\n'|grep "$(printf '[\xff]')" || echo FAIL
  would print FAIL rather than the required matching line.
  [bug introduced in grep-2.6]

  grep's interpretation of range expression is now more consistent with
  that of other tools.  [bug present since multi-byte character set
  support was introduced in 2.5.2, though the steps needed to reproduce
  it changed in grep-2.6]

  grep erroneously returned with exit status 1 on some memory allocation
  failure. [bug present since "the beginning"]


* Noteworthy changes in release 2.7 (2010-09-16) [stable]

** Bug fixes

  grep --include=FILE works once again, rather than working like --exclude=FILE
  [bug introduced in grep-2.6]

  Searching with grep -Fw for an empty string would not match an
  empty line. [bug present since "the beginning"]

  X{0,0} is implemented correctly.  It used to be a synonym of X{0,1}.
  [bug present since "the beginning"]

  In multibyte locales, regular expressions including backreferences
  no longer exhibit quadratic complexity (i.e., they are orders
  of magnitude faster). [bug present since multi-byte character set
  support was introduced in 2.5.2]

  In UTF-8 locales, regular expressions including "." can be orders
  of magnitude faster.  For example, "grep ." is now twice as fast
  as "grep -v ^$", instead of being immensely slower.  It remains
  slow in other multibyte locales. [bug present since multi-byte
  character set support was introduced in 2.5.2]

  --mmap was meant to be ignored in 2.6.x, but it was instead
  removed by mistake.  [bug introduced in 2.6]

** New features

  grep now diagnoses (and fails with exit status 2) commonly mistyped
  regular expression like [:space:], [:digit:], etc.  Before, those were
  silently interpreted as [ac:eps] and [dgit:] respectively.  Virtually
  all who make that class of mistake should have used [[:space:]] or
  [[:digit:]].  This new behavior is disabled when the POSIXLY_CORRECT
  environment variable is set.

  On systems using glibc, grep can support equivalence classes.  However,
  whether they actually work depends on glibc's locale definitions.

* Noteworthy changes in release 2.6.3 (2010-04-02) [stable]

** Bug fixes

  Searching with grep -F for an empty string in a multibyte locale
  would hang grep. [bug introduced in 2.6.2]

  PCRE support is once again detected on systems with <pcre/pcre.h>
  [bug introduced in 2.6.2]


* Noteworthy changes in release 2.6.2 (2010-03-29) [stable]

** Bug fixes

  grep -F no longer mistakenly reports a match when searching
  for an incomplete prefix of a multibyte character.
  [bug present since "the beginning"]

  grep -F no longer goes into an infinite loop when it finds a match for an
  incomplete (non-prefix of a) multibyte character.  [bug introduced in 2.6]

  Using any of the --include or --exclude* options would cause a NULL
  dereference.  [bugs introduced in 2.6]

** Build-related

  configure no longer relies on pkg-config to detect PCRE support.


* Noteworthy changes in release 2.6.1 (2010-03-25) [stable]

** Bug fixes

  Character classes could cause a segmentation fault if they included a
  multibyte character.  [bug introduced in 2.6]

  Character ranges would not work in single-byte character sets other
  than C (for example, ISO-8859-1 or KOI8-R) and some multi-byte locales.
  For example, this should print "1", but would find no match:
    $ echo 1 | env -i LC_COLLATE=en_US.UTF-8 grep '[0-9]'
  [bug introduced in 2.6]

  The output of grep was incorrect for whole-word (-w) matches if the
  patterns included a back-reference. [bug introduced in grep-2.5.2]

** Portability

  Avoid a link failure on Solaris 8.


* Noteworthy changes in release 2.6 (2010-03-23) [stable]

** Speed improvements

  grep is much faster on multibyte character sets, especially (but not
  limited to) UTF-8 character sets.  The speed improvement is also very
  pronounced with case-insensitive matches.

** Bug fixes

  Character classes would malfunction in multi-byte locales when using grep -i.
  Examples which would print nothing for LC_ALL=en_US.UTF-8 include:
  - for ranges, echo Z | grep -i '[a-z]'
  - for single characters, echo Y | grep -i '[y]'
  - for character types, echo Y | grep -i '[[:lower:]]'

  grep -i -o would fail to report some matches; grep -i --color, while not
  missing any line containing a match, would fail to color some matches.

  grep would fail to report a match in a multibyte character set other than
  UTF-8, if another match occurred earlier in the line but started in the
  middle of a multibyte character.

  Various bugs in grep -P, caused by expressions such as [^b] or \S matching
  newlines, were fixed.  grep -P also supports the special sequences \Z and
  \z, and can be combined with the command-line option -z to perform searches
  on NUL-separated records.

  grep would mistakenly exit with status 1 upon error, rather than 2,
  as it is documented to do.

  Using options like -1 -2 or -1 -v -2 results in two lines of
  context (the last value that appears on the command line) instead
  twelve (the concatenation of all the values).  This is consistent
  with the behavior of options -A/-B/-C.

  Two new command-line options, --group-separator=ARGUMENT and
  --no-group-separator, enable further customization of the output
  when -A, -B or -C is being used.

** Other changes

  egrep accepts the -E option and fgrep accepts the -F option.  If egrep
  and fgrep are given another of the -E/-F/-G options, they print a more
  meaningful error message.

* Noteworthy changes in release 2.5.4 (2009-02-10) [stable]

  - This is a bugfix release. No new features.

Version 2.5.3
  - The new option --exclude-dir allows to specify a directory pattern that
    will be excluded from recursive grep.
  - Numerous bug fixes

Version 2.5.1
  - This is a bugfix release. No new features.

Version 2.5
  - The new option --label allows to specify a different name for input
    from stdin. See the man or info pages for details.

  - The internal lib/getopt* files are no longer used on systems providing
    getopt functionality in their libc (e.g. glibc 2.2.x).
    If you need the old getopt files, use --with-included-getopt.

  - The new option --only-matching (-o) will print only the part of matching
    lines that matches the pattern. This is useful, for example, to extract
    IP addresses from log files.

  - i18n bug fixed ([A-Z0-9] wouldn't match A in locales other than C on
    systems using recent glibc builds

  - GNU grep can now be built with autoconf 2.52.

  - The new option --devices controls how grep handles device files. Its usage
    is analogous to --directories.

  - The new option --line-buffered fflush on everyline.  There is a noticeable
    slow down when forcing line buffering.

  - Back references  are now local to the regex.
    grep -e '\(a\)\1' -e '\(b\)\1'
    The last backref \1 in the second expression refer to \(b\)

  - The new option --include=PATTERN will search only matching files
    when recursing in directories

  - The new option --exclude=PATTERN will skip matching files when
    recursing in directories.

  - The new option --color will use the environment variable GREP_COLOR
    (default is red) to highlight the matching string.
    --color takes an optional argument specifying when to colorize a line:
      --color=always, --color=tty, --color=never

  - The following changes are for POSIX.2 conformance:

    . The -q or --quiet or --silent option now causes grep to exit
      with zero status when a input line is selected, even if an error
      also occurs.

    . The -s or --no-messages option no longer affects the exit status.

    . Bracket regular expressions like [a-z] are now locale-dependent.
      For example, many locales sort characters in dictionary order,
      and in these locales the regular expression [a-d] is not
      equivalent to [abcd]; it might be equivalent to [aBbCcDd], for
      example.  To obtain the traditional interpretation of bracket
      expressions, you can use the C locale by setting the LC_ALL
      environment variable to the value "C".

  - The -C or --context option now requires an argument, partly for
    consistency, and partly because POSIX.2 recommends against
    optional arguments.

  - The new -P or --perl-regexp option tells grep to interpert the pattern as
    a Perl regular expression.

  - The new option --max-count=num makes grep stop reading a file after num
    matching lines.
    New option -m; equivalent to --max-count.

  - Translations for bg, ca, da, nb and tr have been added.

Version 2.4.2

  - Added more check in configure to default the grep-${version}/src/regex.c
    instead of the one in GNU Lib C.

Version 2.4.1

  - If the final byte of an input file is not a newline, grep now silently
    supplies one.

  - The new option --binary-files=TYPE makes grep assume that a binary input
    file is of type TYPE.
    --binary-files='binary' (the default) outputs a 1-line summary of matches.
    --binary-files='without-match' assumes binary files do not match.
    --binary-files='text' treats binary files as text
        (equivalent to the -a or --text option).

  - New option -I; equivalent to --binary-files='without-match'.

Version 2.4:

  - egrep is now equivalent to `grep -E' as required by POSIX,
    removing a longstanding source of confusion and incompatibility.
    `grep' is now more forgiving about stray `{'s, for backward
    compatibility with traditional egrep.

  - The lower bound of an interval is not optional.
    You must use an explicit zero, e.g. `x{0,10}' instead of `x{,10}'.
    (The old documentation incorrectly claimed that it was optional.)

  - The --revert-match option has been renamed to --invert-match.

  - The --fixed-regexp option has been renamed to --fixed-string.

  - New option -H or --with-filename.

  - New option --mmap.  By default, GNU grep now uses read instead of mmap.
    This is faster on some hosts, and is safer on all.

  - The new option -z or --null-data causes `grep' to treat a zero byte
    (the ASCII NUL character) as a line terminator in input data, and
    to treat newlines as ordinary data.

  - The new option -Z or --null causes `grep' to output a zero byte
    instead of the normal separator after a file name.

  - These two options can be used with commands like `find -print0',
    `perl -0', `sort -z', and `xargs -0' to process arbitrary file names,
    even those that contain newlines.

  - The environment variable GREP_OPTIONS specifies default options;
    e.g. GREP_OPTIONS='--directories=skip' reestablishes grep 2.1's
    behavior of silently skipping directories.

  - You can specify a matcher multiple times without error, e.g.
    `grep -E -E' or `fgrep -F'.  It is still an error to specify
    conflicting matchers.

  - -u and -U are now allowed on non-DOS hosts, and have no effect.

  - Modifications of the tests scripts to go around the "Broken Pipe"
    errors from bash. See Bash FAQ.

  - New option -r or --recursive or --directories=recurse.
    (This option was also in grep 2.3, but wasn't announced here.)

  - --without-included-regex disable, was causing bogus reports .i.e
    doing more harm then good.

Version 2.3:

  - When searching a binary file FOO, grep now just reports
    `Binary file FOO matches' instead of outputting binary data.
    This is typically more useful than the old behavior,
    and it is also more consistent with other utilities like `diff'.
    A file is considered to be binary if it contains a NUL (i.e. zero) byte.

    The new -a or --text option causes `grep' to assume that all
    input is text.  (This option has the same meaning as with `diff'.)
    Use it if you want binary data in your output.

  - `grep' now searches directories just like ordinary files; it no longer
    silently skips directories.  This is the traditional behavior of
    Unix text utilities (in particular, of traditional `grep').
    Hence `grep PATTERN DIRECTORY' should report
    `grep: DIRECTORY: Is a directory' on hosts where the operating system
    does not permit programs to read directories directly, and
    `grep: DIRECTORY: Binary file matches' (or nothing) otherwise.

    The new -d ACTION or --directories=ACTION option affects directory handling.
    `-d skip' causes `grep' to silently skip directories, as in grep 2.1;
    `-d read' (the default) causes `grep' to read directories if possible,
    as in earlier versions of grep.

  - The MS-DOS and Microsoft Windows ports now behave identically to the
    GNU and Unix ports with respect to binary files and directories.

Version 2.2:

Bug fix release.

  - Status error number fix.
  - Skipping directories removed.
  - Many typos fix.
  - -f /dev/null fix(not to consider as an empty pattern).
  - Checks for wctype/wchar.
  - -E was using the wrong matcher fix.
  - bug in regex char class fix
  - Fixes for DJGPP

Version 2.1:

This is a bug fix release(see Changelog) i.e. no new features.

  - More compliance to GNU standard.
  - Long options.
  - Internationalisation.
  - Use automake/autoconf.
  - Directory hierarchy change.
  - Sigvec with -e on Linux corrected.
  - Sigvec with -f on Linux corrected.
  - Sigvec with the mmap() corrected.
  - Bug in kwset corrected.
  - -q, -L and -l stop on first match.
  - New and improve regex.[ch] from Ulrich Drepper.
  - New and improve dfa.[ch] from Arnold Robbins.
  - Prototypes for over zealous C compiler.
  - Not scanning a file, if it's a directory
    (cause problems on Sun).
  - Ported to MS-DOS/MS-Windows with DJGPP tools.

See Changelog for the full story and proper credits.

Version 2.0:

The most important user visible change is that egrep and fgrep have
disappeared as separate programs into the single grep program mandated
by POSIX 1003.2.  New options -G, -E, and -F have been added,
selecting grep, egrep, and fgrep behavior respectively.  For
compatibility with historical practice, hard links named egrep and
fgrep are also provided.  See the manual page for details.

In addition, the regular expression facilities described in Posix
draft 11.2 are now supported, except for internationalization features
related to locale-dependent collating sequence information.

There is a new option, -L, which is like -l except it lists
files which don't contain matches.  The reason this option was
added is because '-l -v' doesn't do what you expect.

Performance has been improved; the amount of improvement is platform
dependent, but (for example) grep 2.0 typically runs at least 30% faster
than grep 1.6 on a DECstation using the MIPS compiler.  Where possible,
grep now uses mmap() for file input; on a Sun 4 running SunOS 4.1 this
may cut system time by as much as half, for a total reduction in running
time by nearly 50%.  On machines that don't use mmap(), the buffering
code has been rewritten to choose more favorable alignments and buffer
sizes for read().

Portability has been substantially cleaned up, and an automatic
configure script is now provided.

The internals have changed in ways too numerous to mention.
People brave enough to reuse the DFA matcher in other programs
will now have their bravery amply "rewarded", for the interface
to that file has been completely changed.  Some changes were
necessary to track the evolution of the regex package, and since
I was changing it anyway I decided to do a general cleanup.

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