- 4/3/2016 -WindowsnpmgulpYou'll often see following error when running npm command at windows OS system. 'Gulp' is not recognized as an internal or external command, operable program or batch file. 'Bower' is not recognized as an internal or external command, operable program or batch file. 'yo' is not recognized as an internal or external command, operable program or batch file. Basically you have to add to Path to Environment Variables's Path. How to enable gulp? For gulp, you will have to add following path to Path System Variables, so command line will recognize npm's global path. Also install gulp so run command as gulp will be recognized. At the end, you'll have to restart the command line if you have not restart command line after change the system variables.