Delete empty lines into a file

Problem - you have a file that has a huge number of records and in between you have
empty lines.
This is my example.txt file:

asd

asd
as


sd
as

asd

asd

sd
g

To take the spaces off you have at least two simple tools to do it.

• sed with this tool you can achieve your goal just by doing this - open a command line prompt and type the following
  linux$ cat example.txt | sed -e '/^$/d' you will see on your screen the following
  

  asd
  asd
  as
  sd
  as
  asd
  asd
  sd
  g
  

• grep with this we use a trick saying that we don't want certain patterns from the file - the empty lines - open a command line prompt and type the following
  linux$ grep -v '^$' example.txt
  

asd
asd
as
sd
as
asd
asd
sd
g