Removing blank lines from a file

Shell Programming and Scripting
1

Hi All,

How do i remove continuos blank lines from a file.

I have a file with data:

 
abc;
def;
ghi;
 
 
jkl;
mno;
pqr;

In the above file, there are two blank lines. I want to remove, one out of them.

My output should look like:

abc;
def;
ghi;
 
jkl;
mno;
pqr;

With the below command, all the blank lines are getting deleted. I don't want that. I have to remove one out of two blanks.

 
 
sed -i '/^$/d' my_file
2

Try like...

  awk 'NF>0' test.txt
3

The above command is removing all the blank lines. But i want to keep only one blank line if more than one blank lines avail. I want to remove all other blank lines.

---------- Post updated at 06:22 PM ---------- Previous update was at 06:17 PM ----------

awk '/^$/{ if (! blank++) print; next } { blank=0; print }' my_file

or

 
awk 'NR==1 || NF || prvNF {print} {prvNF=NF}' my_file

Any of the above codes are working fine for me..
Thank you all!!!!!!!