36 lines
1.7 KiB
Plaintext
36 lines
1.7 KiB
Plaintext
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Version 2.0:
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The most important user visible change is that egrep and fgrep have
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disappeared as separate programs into the single grep program mandated
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by POSIX 1003.2. New options -G, -E, and -F have been added,
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selecting grep, egrep, and fgrep behavior respectively. For
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compatibility with historical practice, hard links named egrep and
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fgrep are also provided. See the manual page for details.
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In addition, the regular expression facilities described in Posix
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draft 11.2 are now supported, except for internationalization features
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related to locale-dependent collating sequence information.
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There is a new option, -L, which is like -l except it lists
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files which don't contain matches. The reason this option was
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added is because '-l -v' doesn't do what you expect.
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Performance has been improved; the amount of improvement is platform
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dependent, but (for example) grep 2.0 typically runs at least 30% faster
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than grep 1.6 on a DECstation using the MIPS compiler. Where possible,
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grep now uses mmap() for file input; on a Sun 4 running SunOS 4.1 this
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may cut system time by as much as half, for a total reduction in running
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time by nearly 50%. On machines that don't use mmap(), the buffering
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code has been rewritten to choose more favorable alignments and buffer
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sizes for read().
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Portability has been substantially cleaned up, and an automatic
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configure script is now provided.
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The internals have changed in ways too numerous to mention.
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People brave enough to reuse the DFA matcher in other programs
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will now have their bravery amply "rewarded", for the interface
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to that file has been completely changed. Some changes were
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necessary to track the evolution of the regex package, and since
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I was changing it anyway I decided to do a general cleanup.
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