01-02-2008
Line deletion help using perl -ne
Hi all,
I know the one liner to delete all the lines in a file which matches a pattern
i.e
perl -i.old -ne 'print unless /pattern/' file
Now i need the perl onliner to delete all the lines which doesnt match the pattern. Also what is the difference between perl -i and perl -i.old.
Does perl -i.old archive the existing file?
Your help in this will be appreciated.
Thanks in advance.
Lijju
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LEARN ABOUT OSX
svk::log::filter::grep
SVK::Log::Filter::Grep(3) User Contributed Perl Documentation SVK::Log::Filter::Grep(3)
SYNOPSIS
SVK::Log::Filter::Grep - search log messages for a given pattern
DESCRIPTION
The Grep filter requires a single Perl pattern (regular expression) as its argument. The pattern is then applied to the svn:log property
of each revision it receives. If the pattern matches, the revision is allowed to continue down the pipeline. If the pattern fails to
match, the pipeline immediately skips to the next revision.
The pattern is applied with the /i modifier (case insensitivity). If you want case-sensitivity or other modifications to the behavior of
your pattern, you must use the "(?imsx-imsx)" extended pattern (see "perldoc perlre" for details). For example, to search for log messages
that match exactly the characters "foo" you might use
svk log --filter "grep (?-i)foo"
However, to search for "foo" without regards for case, one might try
svk log --filter "grep foo"
The result of any capturing parentheses inside the pattern are not available. If demand dictates, the Grep filter could be modified to
place the captured value somewhere in the stash for other filters to access.
If the pattern contains a pipe character ('|'), it must be escaped by preceding it with a '' character. Otherwise, the portion of the
pattern after the pipe character is interpreted as the name of a log filter.
STASH
/PROPERTY MODIFICATIONS
Grep leaves all properties and the stash intact.
perl v5.10.0 2008-08-04 SVK::Log::Filter::Grep(3)