edited commands to create image in full os guide (#177)

sites/cheerpx/src/content/docs/13-tutorials/full_os.md

@@ -30,15 +30,17 @@ Copy the filesystem from the container into a local directory:
 
 ```bash
 mkdir cheerpXFS
-podman cp cheerpxcontainer:/ cheerpXFS/
+podman unshare podman cp cheerpxcontainer:/ cheerpXFS/
 ```
 
 Create an ext2 image from the specified directory:
 
 ```bash
-mkfs.ext2 -b 4096 -d cheerpXFS/ cheerpXImage.ext2 600M
+podman unshare mkfs.ext2 -b 4096 -d cheerpXFS/ cheerpXImage.ext2 600M
 ```
 
+Learn more about creating a image in the [custom-disk-images] guide.
+
 ## 2. Load CheerpX from your index.html
 
 Loading CheerpX is very simple. Create a new file called `index.html` and populate it with the following HTML code.
@@ -179,3 +181,4 @@ Learn more about `cx.run` in the [CheerpX.Linux.run] reference.
 [CheerpX.Linux.create]: docs/reference/CheerpX-Linux-create
 [setConsole]: docs/reference/CheerpX-Linux-setConsole
 [CheerpX.Linux.run]: docs/reference/CheerpX-Linux-run
+[custom-disk-images]: /docs/guides/custom-images