Shell Programming and Scripting

Another way is to considere any line whith no visible character as a paragraph separator.
Using blank as the default separator , the awk NF variable will by equal to 0 in case you have either blank spaces or nothing.
So this code should fit on most cases :

Code:

awk 'NF{printf "%s" ,$0 ;next}{print ""}' file.txt

But in your sample file from post #4, we must take care of the consecutive empty lines.
I guess this should be seen as one single paragraph separator.

My final code :

Code:

awk 'NF{printf "%s" ,$0 ;nblf=0;next}nblf == 0{print "";nblf++}' file.txt

---------- Post updated at 10:00 PM ---------- Previous update was at 09:16 PM ----------

Using your file 1181.txt , I noticed there is an LF on the first line.
See this code shoud fit better, as this leading empty line will be removed.

Code:

awk 'NF{printf "%s" ,$0 ;istext++;next}istext{print "";istext=0}' 1181.txt  > 1181.res