SED : How to delete N numbers of starting lines from a file using SED

Lets take an example of simple nagios host config file.

Example file name : localhost.cfg

# for the local machine
# A host for the local machine
# Monitoring template
# Define a host for the local machine

define host{
        use                     linux-server                    
        host_name               localhost
        alias                   localhost
        address                 127.0.0.1
        }

Here I want to delete starting 3 lines of my file localhost.cfg
to completely look like as

# Define a host for the local machine
define host{
        use                     linux-server                    
        host_name               localhost
        alias                   localhost
        address                 127.0.0.1
        }

Using sed to delete starting 3 lines of a file

cybeerkeeda@Linux-Maniac:~ sed -i -e "1,3d"   localhost.cfg

Change number 3 with your desired line number you want to delete

Note :

sed  -i  : Here -i    parameter will directly write the changes into the file.

I suggest to take a automatically take up backup during this comand.

cybeerkeeda@Linux-Maniac:~ sed -i.bak -e "1,3d"   localhost.cfg

 Search more SED tutorials on the go here.