Re: to remove leading and trailing blank lines

On 01/07/2013 21:11, Jim Hill wrote:

> I figure buffering's too cheap to meter, so I like this one:
>
>      sed 'H;$!d;g; s/\n*$//; s/^\n*//'

A line-oriented Perl version, with some state, and a DEBUG mode:

echo -e "\n   \n\nx\n    \n\ny\n\nz\n  \n\n" | DEBUG=0 perl -ne'
   $s ||= /\S/ or next;  # skip heading empty lines
   $b .= $_;             # buffer lines
   /\S/ or next;         #   until non-whitespace
   $b =~ s/^(.*)$/<$1>/mg if $ENV{DEBUG};
   print($b);            # print buffer
   $b = "";              # empty buffer
'
x


y

z

-- 
Ruud