Update Docker image in README.md files

The Docker image used in the README.md files has been updated from ubuntu:latest to alpine:latest. This change affects the compiled_starters and
solutions directories for the following languages: C, Go, Nim, PHP, Python, Ruby, Rust, and Swift. The change was made in the course-definition.yml and
starter_templates directories as well.

Commit message: "Update Docker image to alpine:latest in README.md files"

compiled_starters/c/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

compiled_starters/go/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

compiled_starters/nim/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

compiled_starters/php/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

compiled_starters/python/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

compiled_starters/ruby/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

compiled_starters/rust/README.md

@@ -47,7 +47,7 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```
 
 This command compiles your Rust project, so it might be slow the first time you

compiled_starters/swift/README.md

@@ -48,5 +48,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

course-definition.yml

@@ -80,13 +80,13 @@ stages:
       be executed similar to `docker run`:
 
       ```
-      mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+      mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
       ```
 
       [docker-explorer](https://github.com/codecrafters-io/docker-explorer) is a custom test program that exposes
       commands like `echo` and `ls`.
 
-      For now, don't worry about pulling the `ubuntu:latest` image. We will just
+      For now, don't worry about pulling the `alpine:latest` image. We will just
       execute a local program for this stage and print its output. You'll work on
       pulling images from Docker Hub in stage 6.
     marketing_md: |-
@@ -103,7 +103,7 @@ stages:
       Like the last stage, the tester will run your program like this:
 
       ```
-      mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+      mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
       ```
 
       To test this behaviour locally, you could use the `echo` + `echo_stderr`
@@ -137,7 +137,7 @@ stages:
       Just like the previous stage, the tester will run your program like this:
 
       ```
-      mydocker run ubuntu:latest /usr/local/bin/docker-explorer exit 1
+      mydocker run alpine:latest /usr/local/bin/docker-explorer exit 1
       ```
     marketing_md: |-
       In this stage, you'll wait for the child program's exit code and exit with
@@ -192,7 +192,7 @@ stages:
       Just like the previous stage, the tester will run your program like this:
 
       ```
-      mydocker run ubuntu:latest /usr/local/bin/docker-explorer ls /some_dir
+      mydocker run alpine:latest /usr/local/bin/docker-explorer ls /some_dir
       ```
     marketing_md: |-
       In this stage, you'll restrict a program's access to the host filesystem
@@ -224,7 +224,7 @@ stages:
       Just like the previous stage, the tester will run your program like this:
 
       ```
-      mydocker run ubuntu:latest /usr/local/bin/docker-explorer mypid
+      mydocker run alpine:latest /usr/local/bin/docker-explorer mypid
       ```
     marketing_md: |-
       In this stage, you'll restrict a program's access to the host's process
@@ -257,13 +257,13 @@ stages:
       The tester will run your program like this:
 
       ```
-      mydocker run ubuntu:latest /bin/echo hey
+      mydocker run alpine:latest /bin/echo hey
       ```
 
       The image used will be an [official
       image](https://docs.docker.com/docker-hub/official_images/) from Docker
       Hub. For example: [`alpine:latest`](https://hub.docker.com/_/alpine),
-      [`ubuntu:latest`](https://hub.docker.com/_/ubuntu),
+      [`alpine:latest`](https://hub.docker.com/_/alpine),
       [`busybox:latest`](https://hub.docker.com/_/busybox). When interacting with the
       Registry API, you'll need to prepend `library/` to the image names.
 

solutions/c/01-init/code/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

solutions/go/01-init/code/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

solutions/nim/01-init/code/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

solutions/php/01-init/code/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

solutions/python/01-init/code/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

solutions/ruby/01-init/code/README.md

@@ -47,5 +47,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

solutions/rust/01-init/code/README.md

@@ -47,7 +47,7 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```
 
 This command compiles your Rust project, so it might be slow the first time you

solutions/swift/01-init/code/README.md

@@ -48,5 +48,5 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```

starter_templates/README.md

@@ -1,6 +1,5 @@
 ![progress-banner](https://codecrafters.io/landing/images/default_progress_banners/docker.png)
 
-
 This is a starting point for {{language_name}} solutions to the
 ["Build Your Own Docker" Challenge](https://codecrafters.io/challenges/docker).
 
@@ -15,11 +14,11 @@ registry API](https://docs.docker.com/registry/spec/api/) and much more.
 
 # Passing the first stage
 
-The entry point for your Docker implementation is `{{ user_editable_file }}`. 
+The entry point for your Docker implementation is `{{ user_editable_file }}`.
 Study and uncomment the relevant code, and push your changes to pass the first stage:
 
-``` sh
-git add . 
+```sh
+git add .
 git commit -m "pass 1st stage" # any msg
 git push origin master
 ```
@@ -31,14 +30,14 @@ That's all!
 Note: This section is for stages 2 and beyond.
 
 You'll use linux-specific syscalls in this challenge. so we'll run
-your code _inside_ a Docker container. 
+your code _inside_ a Docker container.
 
-Please ensure you have 
+Please ensure you have
 [Docker installed](https://docs.docker.com/get-docker/) locally.
 
 Next, add a [shell alias](https://shapeshed.com/unix-alias/):
 
-``` sh
+```sh
 alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" mydocker'
 ```
 
@@ -47,10 +46,9 @@ alias mydocker='docker build -t mydocker . && docker run --cap-add="SYS_ADMIN" m
 You can now execute your program like this:
 
 ```sh
-mydocker run ubuntu:latest /usr/local/bin/docker-explorer echo hey
+mydocker run alpine:latest /usr/local/bin/docker-explorer echo hey
 ```
 
 {{# language_is_rust }}This command compiles your
 Rust project, so it might be slow the first time you run it. Subsequent runs
 will be fast.{{/ language_is_rust}}
-