Split a paragraph

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1

Hi,
Consider the following paragraph.
This is line1.
This is line2,

This is last line.

I need the output as

4:This is last line.

i.e The line after the blank line should be displayed along with line number.
I am a unix begineer.Any one please help me to solve this problem

2

Hi,

awk 'NF==0 {i=1 ; next}
i==1 { print NR":"$0 ; i=0} ' filename

Thanks
Penchal

3

Many Thanks. Its working fine.

4 
$ awk '
/^$/{
getline
print NR":"$0
}'  file

//Jadu