'gulp' is not recognized as an internal or external command,

I have installed npm and working for the past few months without an issue. I was trying to execute a gulp task and came across the issue of gulp not working. The visual studio output displayed as follows

 'gulp' is not recognized as an internal or external command.

I fixed this issue by re installing gulp using  the following command

npm install -g gulp


Cheers,
Saamitha