Sed question

Gary Kline kline at
Tue Dec 23 19:09:00 UTC 2008

On Mon, Dec 22, 2008 at 08:53:36AM +0000, Matthew Seaman wrote:
> Gary Kline wrote:
> >	anyway, this is one for giiorgos, or another perl wiz. i've
> >	been using the perl subsitution cmd one-liner for years with
> >	unfailing success.  is there a way of deleting lines with perl
> >	using the same idea as:
> >
> >	  perl -pi.bak -e 's/OLDSTRING/NEWSTRING/g' file1 file2 fileN
> To delete lines matching a R.E. (grep -v effectively):
>    perl -ni.bak -e 'm/SOMETHING/ || print;' file1 file2 fileN


	I've been trying, unsuccessfully, to parse the above.  What does
	the "m" [in 'm/SOMETHING/' do.  i thought it was 'match'  ... and
	another one, just FWIW: can perl's regex be set to ignore cases?

> To delete lines by number from many files -- eg. exclude lines 3 to 7:
>    perl -ni.bak -e 'print unless ( 3 .. 7 ); close ARGV if eof;' \
> 	file1 file2 fileN
> The malarkey with 'close ARGV' is necessary because otherwise perl
> won't reset the input line number counter ($.) for each new file.

	yeah, it's pretty important to reset the counter to zero since
	i've got so many files.

	one way to avoid that extended line would be to embed the perl
	string within a /bin/shell script, :-)  Scripts within scripts,
	eh? lol.  Oh: a final question.  does the perl regex match vi's
	/\<foo\> ?  it seemed like this plot in /OLDSTRING/ failed last
	sunday.  i'm not entirely sure, tho.

	thanks much,


> The range expression ( N .. M ) can take matching terms rather than
> line numbers, so you can also do things like:
>    perl -ni.bak -e 'print unless ( m/FIRST/ .. m/SECOND/ )' \
>        file1 file2 fileN
> 	Cheers,
> 	Matthew
> -- 
> Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
>                                                  Flat 3
> PGP:     Ramsgate
>                                                  Kent, CT11 9PW

 Gary Kline  kline at  Public Service Unix
    The 2.17a release of Jottings:

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