diff --git a/README.md b/README.md
index d436443..30226d2 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,9 @@ required):
 
 * **HTTP_USER**: username for HTTP authentication.
 * **HTTP_PASS**: password for HTTP authentication.
-* **REPO_URL**: git repository URL to clone from.
+* **REPO_URL**: git repository URL to clone from. In case you're using a private
+  GitHub repository, you can specify the GitHub username and password like this:
+  `https://username:password@github.com/username/repository`
 
 ## Automated deployment
 
@@ -64,7 +66,8 @@ README.
 This requires defining two additional environment variables:
 
 * **USE_SECRET**: this variable must be set to 'yes' (lowercase).
-* **SECRET (optional)**: the secret you want to use.
+* **SECRET (optional)**: the secret you want to use. Please do not use the `|`
+  character in the secret.
 
 In case you do not specify a secret, it will be automatically generated. In that
 case, you'll need to check the container logs and look for the string "Secret to
diff --git a/entrypoint.sh b/entrypoint.sh
index ac0ea8e..1b15a54 100644
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -8,9 +8,9 @@ function startup {
   echo "Secret to send posts with: $SECRET"
 
   # Replaces REPO_URL for the one passed as an environment variable.
-  sed -i 's@REPO_URL@'"$REPO_URL"'@g' /bin/generate-html.sh
+  sed -i 's|REPO_URL|'"$REPO_URL"'|g' /bin/generate-html.sh
   # Replaces SECRET expected in posts requests for the randomly generated one.
-  sed -i 's@__SECRET@'"$SECRET"'@g' /bin/generate-html.sh
+  sed -i 's|__SECRET|'"$SECRET"'|g' /bin/generate-html.sh
 
   echo "www-data ALL=(root) NOPASSWD: /bin/generate-html.sh" >> /etc/sudoers
   htpasswd -bc /etc/nginx/.htpasswd $HTTP_USER $HTTP_PASS