Apply technical requirements (R1, R2, R9, R10, R13)

- R1: Add AWS_REGION to region fallback chain
- R2: Replace openssl rand with /dev/urandom
- R9: Remove Appendix/Generation details from READMEs
- R10: Remove internal references
- R13: Add REVISION-HISTORY.md

Author: mwunderl

tuts/141-aws-savingsplans-gs/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 141-aws-savingsplans-gs
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/142-aws-servicecatalog-gs/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 142-aws-servicecatalog-gs
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/142-aws-servicecatalog-gs/aws-servicecatalog-gs.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/sc.log") 2>&1
-REGION=${AWS_DEFAULT_REGION:-$(aws configure get region 2>/dev/null)}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
-RANDOM_ID=$(openssl rand -hex 4); PORTFOLIO="tut-portfolio-${RANDOM_ID}"
+REGION=${AWS_DEFAULT_REGION:-${AWS_REGION:-$(aws configure get region 2>/dev/null))}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
+RANDOM_ID=$(cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 8 | head -n 1); PORTFOLIO="tut-portfolio-${RANDOM_ID}"
 handle_error() { echo "ERROR on line $1"; trap - ERR; cleanup; exit 1; }; trap 'handle_error $LINENO' ERR
 cleanup() { echo ""; echo "Cleaning up..."; [ -n "$PORT_ID" ] && aws servicecatalog delete-portfolio --id "$PORT_ID" 2>/dev/null && echo "  Deleted portfolio"; rm -rf "$WORK_DIR"; echo "Done."; }
 echo "Step 1: Creating portfolio: $PORTFOLIO"

tuts/150-aws-sso-admin-gs/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 150-aws-sso-admin-gs
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/150-aws-sso-admin-gs/aws-sso-admin-gs.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/sso.log") 2>&1
-REGION=${AWS_DEFAULT_REGION:-$(aws configure get region 2>/dev/null)}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
+REGION=${AWS_DEFAULT_REGION:-${AWS_REGION:-$(aws configure get region 2>/dev/null))}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
 echo "Step 1: Listing IAM Identity Center instances"
 INSTANCE_ARN=$(aws sso-admin list-instances --query 'Instances[0].InstanceArn' --output text 2>/dev/null)
 if [ -z "$INSTANCE_ARN" ] || [ "$INSTANCE_ARN" = "None" ]; then echo "  No IAM Identity Center instance found. Enable it in the console first."; rm -rf "$WORK_DIR"; exit 0; fi

tuts/157-cloudformation-stacks/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 157-cloudformation-stacks
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/157-cloudformation-stacks/cloudformation-stacks.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/cfn.log") 2>&1
-REGION=${AWS_DEFAULT_REGION:-$(aws configure get region 2>/dev/null)}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
-RANDOM_ID=$(openssl rand -hex 4); STACK_NAME="tut-stack-${RANDOM_ID}"
+REGION=${AWS_DEFAULT_REGION:-${AWS_REGION:-$(aws configure get region 2>/dev/null))}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
+RANDOM_ID=$(cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 8 | head -n 1); STACK_NAME="tut-stack-${RANDOM_ID}"
 handle_error() { echo "ERROR on line $1"; trap - ERR; cleanup; exit 1; }; trap 'handle_error $LINENO' ERR
 cleanup() { echo ""; echo "Cleaning up..."; aws cloudformation delete-stack --stack-name "$STACK_NAME" 2>/dev/null; aws cloudformation wait stack-delete-complete --stack-name "$STACK_NAME" 2>/dev/null && echo "  Stack deleted"; rm -rf "$WORK_DIR"; echo "Done."; }
 echo "Step 1: Creating a CloudFormation template"

tuts/163-cloudwatch-metrics-math/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 163-cloudwatch-metrics-math
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/163-cloudwatch-metrics-math/cloudwatch-metrics-math.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/cw-math.log") 2>&1
-REGION=${AWS_DEFAULT_REGION:-$(aws configure get region 2>/dev/null)}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
-RANDOM_ID=$(openssl rand -hex 4); NS="Tutorial/App-${RANDOM_ID}"
+REGION=${AWS_DEFAULT_REGION:-${AWS_REGION:-$(aws configure get region 2>/dev/null))}; [ -z "$REGION" ] && echo "ERROR: No region" && exit 1; export AWS_DEFAULT_REGION="$REGION"; echo "Region: $REGION"
+RANDOM_ID=$(cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 8 | head -n 1); NS="Tutorial/App-${RANDOM_ID}"
 cleanup() { echo ""; echo "No cleanup needed — custom metrics expire automatically."; rm -rf "$WORK_DIR"; }
 echo "Step 1: Publishing high-resolution metrics"
 for i in $(seq 1 10); do