Re: replacing blank lines

The problem is you're reading the file one line at a time. If you find a blank line, you're essentially replacing it with another blank line, so there's no net change. If you process it one line at a time, you need to write nonblank lines out to a separate file as you go, so it will have the nonblanks when you're done. If you know the file won't be too big, I think you could also use this regex:

$entire_file =~ s/^\n$//mg;
[download]

That should leave $entire_file with only nonblank lines. HTH.

Comment on Re: replacing blank lines Download Code

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Re: Re: replacing blank lines by KM (Priest) on Mar 06, 2001 at 05:03 UTC
$entire_file =~ s/^\n$//mg; That should leave $entire_file with only nonblank lines This is assuming that blank lines are TRUELY blank (no spaces). This is more general: `perl -pi -e 's!^\s+?$!!' file.txt or s!^(\n\|\s+)$!!g` [download] Cheers, KM	[reply] [d/l]
Re: Re: Re: replacing blank lines by merlyn (Sage) on Mar 06, 2001 at 05:39 UTC
Still far too much typing: `perl -ni -e 'print if /\S/' file.txt` [download] -- Randal L. Schwartz, Perl hacker	[reply] [d/l]
Re: Re: Re: replacing blank lines by chipmunk (Parson) on Mar 06, 2001 at 08:20 UTC
The first one-liner will not have the intended effect: `perl -pi -e 's,^\s+?$,,' file.txt` only works on lines that consist of a newline. For lines that contain whitespace followed by a newline, the newline is not removed because of the non-greedy quantifier. (Although you could run the one-liner twice... ;) In the second one-liner: `perl -pi -e 's,^(\n\|\s+)$,,g' file.txt` the alternation and the /g are unnecessary. This is sufficient: `perl -pi -e 's,^\s+$,,' file.txt`	[reply] [d/l] [select]