Update tutorial_docker.md

Author: fcyu

docs/tutorial_docker.md

@@ -5,6 +5,6 @@
 - (optional) Check the pulled image: `docker image ls -a`
 - Create a Docker container: `docker run -it -v <host directory>:<container directory> fcyucn/fragpipe /bin/bash`. `<host directory>` is the directory in your host machine, and `<container directory>` is the directory you want to map the host directory to container.
 - Then, you have entered the docker, and FragPipe is located in `/fragpipe_bin`
-- Go to `/fragpipe_bin/fragPipe-x.x/fragpipe/bin` directory and execute `./fragpipe --help` in the terminal
+- Go to `/fragpipe_bin/fragpipe-x.x/fragpipe-x.x/bin` directory and execute `./fragpipe --help` in the terminal
 
 Read more: Check [Running FragPipe in command line interface](https://fragpipe.nesvilab.org/docs/tutorial_headless.html) for the instructions running FragPipe in command line interface.