Release notes for ack 3.000

New features

ack 3 is a greplike tool optimized for searching large code trees.

Improvements over ack 2 include:

• Improved -w means more accurate searching for words.

• -w option will warn if your pattern does not lend itself to word matching.

• -i, -I and --smart-case

• --proximate=N option

• --underline option for showing matches without color coding.

• Added --pod and --markdown.

• Added GNUmakefile to the list of makefile specs.

• Added -S as a synonym for --smart-case.

• Added many more checks for mutually exclusive command-line options.

• Added a filetype for SVG files.

Bug fixes

• Column numbers were not getting colorized in the output. Added --color-colno option and ACK_COLOR_COLNO environment variable.

• A pattern that wanted whitespace at the end could match the linefeed at the end of a line. This is no longer possible.

Incompatibilities with ack 2

ack 3 requires Perl 5.10.1

ack 2 only needed Perl 5.8.8. This shouldn’t be a problem since 5.10.1 has been out since 2009.

-w is fussier

ack 3 will not allow you to use -w with a pattern that doesn’t begin or end with a word character.

ack 3 no longer highlights capture groups.

ack 2 would highlight your capture groups. For example,

ack '(set|get)_foo_(name|id)'

would highlight the set or get, and the name or id, but not the full set_user_id that was matched.

This feature was too confusing and has been removed. Now, the entire matching string is highlighted.

ack 3’s –output allows fewer special variables

In ack 2, you could put any kind of Perl code in the --output option and it would get evaluated at run time, which would let you do tricky stuff like this gem from Mark Fowler (http://www.perladvent.org/2014/2014-12-21.html):

ack --output='$&: @{[ eval "use LWP::Simple; 1" && length LWP::Simple::get($&) ]} bytes' \
                'https?://\S+' list.txt
http://google.com/: 19529 bytes
http://metacpan.org/: 7560 bytes
http://www.perladvent.org/: 5562 bytes

This has been a security problem in the past, and so in ack 3 we no longer eval the contents of --output. You’re now restricted to the following variables: $1 thru $9, $_, $., $&, $` , $' and $+. You can also embed \t, \n and \r , and $f as stand-in for $filename in ack2 --output .

ack 3 no longer uses the ACK_OPTIONS environment variable

The ACK_OPTIONS variable was used to supply command line arguments to ack invocations. This has been removed. Use an ackrc file instead.

ack 3 no longer has the --lines option

The --lines option let you select a specific range of lines to print, and not match. There are other better ways to do this (sed, for example).

The --man option no longer uses perldoc

The --man option would use the external perldoc program for displaying documentation. However, this was causing portability problems since some users might not have it installed. The downside is that the text rendering is not quite as pretty.