Re^2: Removing double carriage return

[dragooneye]

My updated code that seems to work. Thanks again pvaldes for your help!

pvaldes' code:

while (<>) {
next if $_ =~ m/\n{1}/;
if ($_ =~ m/\n{2}){s/\n{2}/\n/gs}
elsif ($_ =~ m/\n{3,}){s/\n{3,}/\n\s/gs}
}

Mine:

while (<>) {
     if ($_ =~ m/\n{1}/) {
     }
     if ($_ =~ m/\n{2}/){
          s/\n{2}/\n/gs;
          print;
     }
     elsif ($_ =~ m/\n{3,}/){
          s/\n{3,}/\n/gs;
          print;
     }
}

Above does not work. Below now works (prob a crude way of doing it. Please reply if you have a more elegant way):

while (<>) {
     if ($_ =~ m/\S\n{2}\S/){
          s/(\S)\n{2}(\S)/$1\n$2/gs;
          print;
     }
     elsif ($_ =~ m/\n{3,}/){
          s/\n{3,}/\n\n/gs;
          print;
     }
}

[Cristoforo]

From the command line, this replaces 3 or more newlines with 2 newlines or replaces exactly 2 newlines with 1 newline.

perl -i.bak -0777 -pe 's/(\n{3,}|\n\n)/2 == length $1 ? "\n" : "\n\n"/eg' inputfile

Notice that this looks for the longest match first (so that 2 newlines won't match more than 2, i.e. 3 or more).

Update: That could be simplified to:

perl -i.bak -0777 -pe 's/\n+/2 < length $& ? "\n\n" : "\n"/ge' inputfile

[dragooneye]

Sorry for the late reply. Thanks Cristoforo for the one liner solution. I'll need to read up on the slurp switch. I hope that this will help others.

[pvaldes]

That's better than my code yep, like this you catch a last case that I was missing: a file without any \n. Your code is basically the same as this, but probably don't hurt if you add a last small else only to caught this cases and help in future reviews

while (<>) {
     if ($_ =~ m/\S\n{2}\S/){
          s/(\S)\n{2}(\S)/$1\n$2/gs;
          print;
     }
     elsif ($_ =~ m/\n{3,}/){
          s/\n{3,}/\n\n/gs;
          print;
     }
     else {print;} # do nothing (when you have 0 or 1 \n) 
}