Executes commands during the build phase.
Useful when you are pre-processing source files, for example gathering and processing files that are outside of the input directory.
Executes build commands in parallel.
Returns a promise that resolves when all commands have completed.
contextObject the processing context.
optionsObject the plugin options.
commandsString|Array list of commands to execute.
watchBoolean=true execute commands in watch mode.
Errorif the commands option is invalid.
Errorif the command execution fails.