diff --git a/listings/exercises/ex05-networking/commands.sh b/listings/exercises/ex05-networking/commands.txt
old mode 100755
new mode 100644
similarity index 97%
rename from listings/exercises/ex05-networking/commands.sh
rename to listings/exercises/ex05-networking/commands.txt
index 303f210..9c24c00
--- a/listings/exercises/ex05-networking/commands.sh
+++ b/listings/exercises/ex05-networking/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 5 — Container Networking
 
 podman network create appnet
diff --git a/listings/exercises/ex06-bind-mount/commands.sh b/listings/exercises/ex06-bind-mount/commands.txt
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new mode 100644
similarity index 97%
rename from listings/exercises/ex06-bind-mount/commands.sh
rename to listings/exercises/ex06-bind-mount/commands.txt
index 39954b4..d42b409
--- a/listings/exercises/ex06-bind-mount/commands.sh
+++ b/listings/exercises/ex06-bind-mount/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 6 — Bind Mounts
 
 # Terminal 1: write dates to /tmp/output (detached)
diff --git a/listings/exercises/ex07-named-volume/commands.sh b/listings/exercises/ex07-named-volume/commands.txt
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new mode 100644
similarity index 97%
rename from listings/exercises/ex07-named-volume/commands.sh
rename to listings/exercises/ex07-named-volume/commands.txt
index c637232..3fadbb2
--- a/listings/exercises/ex07-named-volume/commands.sh
+++ b/listings/exercises/ex07-named-volume/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 7 — Named Volumes (shared between containers)
 
 podman volume create pizza
diff --git a/listings/exercises/ex08-persistence/commands.sh b/listings/exercises/ex08-persistence/commands.txt
old mode 100755
new mode 100644
similarity index 97%
rename from listings/exercises/ex08-persistence/commands.sh
rename to listings/exercises/ex08-persistence/commands.txt
index 9a06c55..7ef4609
--- a/listings/exercises/ex08-persistence/commands.sh
+++ b/listings/exercises/ex08-persistence/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 8 — Volume Persistence (data survives container removal)
 
 podman volume create pasta
diff --git a/listings/exercises/ex09-env-variables/commands.sh b/listings/exercises/ex09-env-variables/commands.txt
old mode 100755
new mode 100644
similarity index 97%
rename from listings/exercises/ex09-env-variables/commands.sh
rename to listings/exercises/ex09-env-variables/commands.txt
index 835bac7..fa90f77
--- a/listings/exercises/ex09-env-variables/commands.sh
+++ b/listings/exercises/ex09-env-variables/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 9 — Environment Variables
 
 # Single variables via -e
diff --git a/listings/exercises/ex13-multistage/commands.sh b/listings/exercises/ex13-multistage/commands.txt
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new mode 100644
similarity index 93%
rename from listings/exercises/ex13-multistage/commands.sh
rename to listings/exercises/ex13-multistage/commands.txt
index d72e272..8dfe0b4
--- a/listings/exercises/ex13-multistage/commands.sh
+++ b/listings/exercises/ex13-multistage/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 13 — Multi-stage Build
 
 # Build
diff --git a/listings/exercises/ex14-push/commands.sh b/listings/exercises/ex14-push/commands.txt
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new mode 100644
similarity index 96%
rename from listings/exercises/ex14-push/commands.sh
rename to listings/exercises/ex14-push/commands.txt
index 478bab0..47a44c7
--- a/listings/exercises/ex14-push/commands.sh
+++ b/listings/exercises/ex14-push/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 14 — Push image to local registry
 
 # Tag and push
diff --git a/listings/exercises/ex15-registry-api/commands.sh b/listings/exercises/ex15-registry-api/commands.txt
old mode 100755
new mode 100644
similarity index 96%
rename from listings/exercises/ex15-registry-api/commands.sh
rename to listings/exercises/ex15-registry-api/commands.txt
index 78c27d0..b1c7119
--- a/listings/exercises/ex15-registry-api/commands.sh
+++ b/listings/exercises/ex15-registry-api/commands.txt
@@ -1,4 +1,3 @@
-#!/bin/bash
 # Exercise 15 — Query the local registry API
 
 # List all repositories in the registry
diff --git a/listings/exercises/ex16-local-registry/commands.txt b/listings/exercises/ex16-local-registry/commands.txt
new file mode 100644
index 0000000..bd77409
--- /dev/null
+++ b/listings/exercises/ex16-local-registry/commands.txt
@@ -0,0 +1,19 @@
+# Exercise 16 — Start a local registry and push the VisitCounter
+
+# Start the registry container
+podman run -d --name local-registry -p 5000:5000 registry:2
+
+# Build the VisitCounter image
+cd listings/visitcounter/app
+podman build -t localhost:5000/visitcounter:latest .
+
+# Push to the local registry
+podman push --tls-verify=false localhost:5000/visitcounter:latest
+
+# Verify: list all repositories
+curl http://localhost:5000/v2/_catalog
+# → {"repositories":["visitcounter"]}
+
+# Verify: list tags
+curl http://localhost:5000/v2/visitcounter/tags/list
+# → {"name":"visitcounter","tags":["latest"]}
diff --git a/listings/exercises/ex17-update-cycle/commands.txt b/listings/exercises/ex17-update-cycle/commands.txt
new file mode 100644
index 0000000..43e76b2
--- /dev/null
+++ b/listings/exercises/ex17-update-cycle/commands.txt
@@ -0,0 +1,18 @@
+# Exercise 17 — Full update cycle (edit → build → push → restart)
+
+# 1. Change the page title in main.go
+sed -i 's|<h1>VisitCounter</h1>|<h1>My Counter</h1>|' \
+  listings/visitcounter/app/main.go
+
+# 2. Rebuild
+cd listings/visitcounter/app
+podman build -t localhost:5000/visitcounter:latest .
+
+# 3. Push
+podman push --tls-verify=false localhost:5000/visitcounter:latest
+
+# 4. Restart the Quadlet service
+systemctl --user restart visitcounter-app.service
+
+# 5. Verify — new title should appear
+curl localhost:8080
diff --git a/listings/exercises/ex18-quadlets/commands.txt b/listings/exercises/ex18-quadlets/commands.txt
new file mode 100644
index 0000000..40d72c5
--- /dev/null
+++ b/listings/exercises/ex18-quadlets/commands.txt
@@ -0,0 +1,31 @@
+# Exercise 18 — Deploy VisitCounter via Quadlets
+
+# Create the Quadlet directory
+mkdir -p ~/.config/containers/systemd/
+
+# Copy all Quadlet unit files
+cp listings/visitcounter/quadlets/* ~/.config/containers/systemd/
+
+# Reload systemd to pick up the new units
+systemctl --user daemon-reload
+
+# Check that units were generated
+systemctl --user list-unit-files | grep visitcounter
+# → visitcounter-app.service     generated
+# → visitcounter-db.service      generated
+# → visitcounter-proxy.service   generated
+
+# Start only the proxy — systemd resolves After= dependencies automatically
+systemctl --user start visitcounter-proxy.service
+
+# Verify all three services are running
+systemctl --user status visitcounter-db.service
+systemctl --user status visitcounter-app.service
+systemctl --user status visitcounter-proxy.service
+
+# Test
+curl localhost:8080
+
+# Bonus: kill the app container and watch systemd restart it
+podman stop systemd-visitcounter-app
+systemctl --user status visitcounter-app.service
diff --git a/listings/exercises/ex19-harden/commands.txt b/listings/exercises/ex19-harden/commands.txt
new file mode 100644
index 0000000..5935680
--- /dev/null
+++ b/listings/exercises/ex19-harden/commands.txt
@@ -0,0 +1,64 @@
+# Exercise 19 — Harden a container step by step
+
+# Baseline — works fine
+podman run -d --name insecure -p 8080:80 nginx:1.27
+curl localhost:8080
+podman rm -f insecure
+
+# Step 1: read-only filesystem
+podman run -d --name step1 -p 8080:80 --read-only nginx:1.27
+podman logs step1
+# → fails: mkdir /var/cache/nginx/client_temp: Read-only file system
+podman rm -f step1
+
+podman run -d --name step1 -p 8080:80 \
+  --read-only \
+  --tmpfs /var/cache/nginx \
+  --tmpfs /var/run \
+  nginx:1.27
+curl localhost:8080
+podman rm -f step1
+
+# Step 2: no-new-privileges
+podman run -d --name step2 -p 8080:80 \
+  --read-only \
+  --tmpfs /var/cache/nginx \
+  --tmpfs /var/run \
+  --security-opt no-new-privileges \
+  nginx:1.27
+curl localhost:8080
+podman rm -f step2
+
+# Step 3: drop all capabilities
+podman run -d --name step3 -p 8080:80 \
+  --read-only \
+  --tmpfs /var/cache/nginx \
+  --tmpfs /var/run \
+  --security-opt no-new-privileges \
+  --cap-drop ALL \
+  nginx:1.27
+podman logs step3
+# → fails: bind() to 0.0.0.0:80 failed (13: Permission denied)
+podman rm -f step3
+
+# Step 4: add back only what nginx needs
+podman run -d --name secure -p 8080:80 \
+  --read-only \
+  --tmpfs /var/cache/nginx \
+  --tmpfs /var/run \
+  --security-opt no-new-privileges \
+  --cap-drop ALL \
+  --cap-add CHOWN \
+  --cap-add SETUID \
+  --cap-add SETGID \
+  --cap-add NET_BIND_SERVICE \
+  nginx:1.27
+
+curl localhost:8080
+# → 200 OK
+
+# Inspect the final capability set
+podman inspect secure \
+  --format 'Add: {{.HostConfig.CapAdd}}  Drop: {{.HostConfig.CapDrop}}'
+
+podman rm -f secure