Plugin to spawn a CLI program for piping with gulp. Uses spawn.

gulp-spawn options follow child_process.spawn conventions.

Not all CLI programs support piping. In fact, many newer ones don't. Some programs require that you pass certain arguments if you intend to use stdin and/or stdout. Please check the documentation of the program you intend to use to ensure piping is supported.

The following example pipes image files to ImageMagick's convert. In the case of convert, you must specify a - before arguments and after arguments if you wish to use stdin and stdout, respectively.

import spaw from "gulp-spawn";

// example using ImageMagick's convert
// setting "buffer: false" optional but recommended for heavy I/O
gulp
  .src("./src/images/*.{jpg,png,gif}", { buffer: false })
  .pipe(
    spawn({
      cmd: "convert",
      args: ["-", "-resize", "50%", "-"],
      // optional
      opts: { cwd: "." },
      filename: function (base, ext) {
        return base + "-half" + ext;
      },
    })
  )
  .pipe(gulp.dest("./dist/images/"));

If you write spawn programs please consider taking the time to support stdin & stdout. Piping is one of the many reasons UNIX systems have endured the test of time.