@import "bootstrap"

applications/_shared_assets/features/bootstrap-sass/assets/stylesheets/_bootstrap.scss
applications/_shared_assets/features/bootstrap-sass/assets/stylesheets/_bootstrap-compass.scss
...

applications/
dist/
gulpfile.js
config.js
...

gulp.task('build-sass', function() {
  return gulp.src(settings.sass_files)
    // gulp.src(settings.sass_files, { base: "./" })
    .pipe(sass({
      outputStyle: 'compressed',
      onError: browserSync.notify,
      loadPaths: [
        "applications/_shared_assets/features/bootstrap-sass/assets/stylesheets/"
      ]
    }))
    .pipe(prefix(['last 15 versions', '> 1%', 'ie 8', 'ie 7'], { cascade: true }))
    .pipe(gulp.dest(public_dir))
    // .pipe(gulp.dest("."))
    .pipe(browserSync.reload({ stream: true }));
});

File to import not found or not readable