Deleting only two blank lines

[NTOldTimer]

I have text files that get created with multible blank lines that I'd like to get rid of. I can use the regular expression ^$ to identify a blank line and delete them all but really I'd just like to delete blank lines only if there are two of them together. Is there a regular expression I can write that will identify two blank lines together and delete only one of them?

 

[feherke]

Hi

You mean, 2 or more consecutive empty lines to be reduced to 1 empty lines ?

perl -pe '$b=0if/./;$_=undef if$b++>1' /input/file

[gray]# or[/gray]

perl -ne '$b=0if/./;print if$b++<2' /input/file

Feherke.

http://free.rootshell.be/~feherke/