delete blank lines in a txt file

supernewbie has asked for the wisdom of the Perl Monks concerning the following question:

Perl Masters:
Say I have a txt file like this:

blahblahblahblahblahblah blahblah blahblah blahblahblahblah blahblahbl
+ahblahblahblah! blahblah blahblah blahblah blahblahblahblah.

blahblahblahblahblah, blahblahblahblahblahblahblahblah blah

blahblah blahblah blahblahblahblahblahblah; blahblahblahblah!

blahblahblahblah, blahblahblahblah blahblahblahblah blahblahblahblah. 
+blahblahblahblah, blahblah.
[download]

How could I use powerful Perl to relace the three blank lines with spaces? and get something like this:

 
blahblahblahblahblahblah blahblah blahblah blahblahblahblah blahblahbl
+ahblahblahblah! blahblah blahblah blahblah blahblahblahblah. blahblah
+blahblahblah, blahblahblahblahblahblahblahblah blah blahblah blahblah
+ blah blahb lahblahblahblah; blahblahblahblah!blahblahblahblah, blahb
+lahblahblah blahblahblahblah blahblahblahblah. blahblahblahblah, blah
+blah.
[download]

I've tried something like s/\n/ /; and it did't work. Please enlighten me.... Thank you...

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Re: delete blank lines in a txt file by cLive ;-) (Prior) on Jul 20, 2001 at 21:01 UTC
you need to make it a global replace, by adding a modifier, ie: `s/\n//g;` [download] That's assuming you have the whole file in a string. If you have it in an array, use grep to do it: `@array = grep /\S/, @array;` [download] Where \S represents a non space character - ie, only keep lines that contain non-space characters. cLive ;-)	[reply] [d/l] [select]
Re: delete blank lines in a txt file by larryk (Friar) on Jul 20, 2001 at 20:14 UTC
one of the following from the command line should do the trick: `perl -i.bak -ne "print if /./" filename` [download] or, to get rid of _all_ the newlines: `perl -i.bak -ne "chomp, print if /./" filename` [download] "Argument is futile - you will be ignorralated!"	[reply] [d/l] [select]
Re: delete blank lines in a txt file by Wookie (Beadle) on Jul 20, 2001 at 20:22 UTC
Assuming the blank lines are just carriage returns - the following should work: `#!/usr/bin/perl -w use strict; open (IN,"blah.file")\|\|die ("Failed to open file blah.file\n$!"); open (OUT,"blah.file.nospace")\|\|die("Failed to open file blah.file.out + for writing\n$!"); my $count=0; while (<IN>) { chomp $_; if ($_=~m/^$/g) { $count++; } else { print OUT "$_\n"; } } close IN; close OUT; print 'Deleted '."$count".' blank lines'."\n"; exit (0);` [download] If you think you may have white spaces on your empty line - then you can change the line that reads: `if ($_=~m/^$/g) {` [download] to read: `if ($_=~m/^\s*$/g) {` [download] Hope this helps :) game(Wookie,opponent) eq 'Wookie' ? undef $problem : remove_limbs(arms,opponent);	[reply] [d/l] [select]