In the man page for grep it says: 

 -P, --perl-regexp
              Interpret PATTERN as a Perl regular expression.

[download]

When I try this I get: 

$ grep -P 'whatever'
grep: The -P option is not supported

[download]

(Using Ubuntu 6.06 Dapper Drake)

Any ideas on the history of this feature? Why is it "not supported"? How do I get a version of grep that supports it?

When the feature works, what is the extent of greps support for Perl regexps? Does it actually use perl, or is it a reimplemented engine?

-Andrew.

In reply to grep -P by tomazos

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