Sed question
Matthew Seaman
m.seaman at infracaninophile.co.uk
Mon Dec 22 08:53:51 UTC 2008
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
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.
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: http://www.infracaninophile.co.uk/pgpkey Ramsgate
Kent, CT11 9PW
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