Getting a text file rid of all superfluous blank lines

[Paul Smith]

On 11/30/05, Tim <ignored_mailbox at yahoo.com.au> wrote:
> Tim:
>
> >> I used to know of something that did that (something with various
> >> different reformatting options for massaging text files), but I can't
> >> think what it was.  Quickly looking at the man file for the cat program,
> >> you could do something like:
> >>
> >> cat --squeeze-blank inputfilename -> outputfilename
>
> Paul Smith:
> > Thanks, Tim and Paul. Paul's method does not mysteriously work:
> >
> > $ more file1.txt
> > word1
> >
> >
> >
> > word2
> >
> > word3
> > $ more -s file1.txt > file2.txt
> > $ more file2.txt
> > word1
> >
> >
> >
> > word2
> >
> > word3
>
> Hmm, seems to work for me.  Both with the "less" and "more" programs, as
> well as the "cat" program.
>
> > Tim's way works partially, i.e., many blank lines are in effect
> > erased, but some remain. I suspect that the left blank lines are not
> > blank lines although they look like blank lines. Can one go further
> > with deleting the left "false" blank lines?
>
> In what way do they remain?  Can you provide an actual example?  (Rather
> than an explanation of what's happening.)
>
> What I see is that all consecutive blank lines are replaced by a single
> blank line, on the file I tried it with.
>
> e.g. Tested on /etc/selinux/targeted/contexts/files/file_contexts
>
> If you want to remove all blank lines, then perhaps you could use grep.

Thanks, Tim. Rodolfo's technique works fine for me. It reduced about
40Kb of a HTML document produced by NVU. I do not know why, but NVU
seems to add blocks of blank lines, drastically increasing the size of
the document.

Paul