Add options parameters in Gulp to be used like:
gulp build --myopt1 --myopt2 --myopt3=valnpm install gulp-optionsvar gulp = require('gulp');
var options = require('gulp-options');
gulp.task('mytask', function() {
    if (options.has('prod')) {
        // Do prod stuff...
        return gulp.src('src/**/*.*').pipe(gulp.dest('release/'));
    } else if (options.has('debug')) {
        // Do debug stuff..
        return gulp.src('src/**/*.*').pipe(gulp.dest('debug/'));
    } else {
        // Do default stuff..
        return gulp.src('src/**/*.*').pipe(gulp.dest('dev/'));
    }
    // Get option value
    if (options.has('env')) {
        const env = options.get('env');
        return gulp.src('src/**/*.*').pipe(gulp.dest(`${env}/`));
    }
});gulp mytask --prod          # source files moved to  release/ folder
gulp mytask --debug         # source files moved to  debug/ folder
gulp mytask --env=customenv # source files moved to  customenv/ folder
gulp mytask                 # source files moved to  dev/ folder