1. Build the image:

   docker build -t tgs-to-gif .

2. Convert! Pass directory with stickers and run:

   docker run --rm -v <path to directory with stickers>:/source tgs-to-gif

The result will be saved next to each source sticker file in the same directory.

1. Install nodejs.
2. Install gifski.
3. Install npm dependencies:

   npm install

Pass one or several stickers:

node cli.js sticker1.tgs sticker2.tgs ... 

or pass a directory:

node cli.js /home/ed/Downloads/super_pack/

The result will be saved next to each source sticker file in the same directory.

$ node cli.js --help
usage: cli.js [-h] [--height HEIGHT] [--width WIDTH] paths [paths ...]

Animated stickers for Telegram (*.tgs) to animated GIFs converter

Positional arguments:
  paths            Paths to .tgs files to convert

Optional arguments:
  -h, --help       Show this help message and exit.
  --height HEIGHT  Output image height. Default: auto
  --width WIDTH    Output image width. Default: auto

You can download .tgs files using @Stickerdownloadbot.