When writing a vim plugin interacting with different programs on the server might be necessary. For instance you might want to use
ruby to make a network request or perform some file management. But first, the vim plugin should check to see if the program
ruby exists which can be accomplished with the
executable() vimscript function.
:echo executable('ruby') 1
:echo executable('doesnotexist') 0
This can be used in a condition before running the
if executable('ruby') system('ruby -e "puts YAML"') endif