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/203-dynamodb-batch-operations/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 203-dynamodb-batch-operations
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/203-dynamodb-batch-operations/dynamodb-batch-ops.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/tut.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); T="tut-batch-${RANDOM_ID}"
+REGION=${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); T="tut-batch-${RANDOM_ID}"
 cleanup() { aws dynamodb delete-table --table-name "$T" > /dev/null 2>&1; rm -rf "$WORK_DIR"; echo "Done."; }
 echo "Step 1: Creating table"; aws dynamodb create-table --table-name "$T" --key-schema AttributeName=pk,KeyType=HASH --attribute-definitions AttributeName=pk,AttributeType=S --billing-mode PAY_PER_REQUEST > /dev/null; aws dynamodb wait table-exists --table-name "$T"
 echo "Step 2: Batch write (25 items)"; aws dynamodb batch-write-item --request-items "{\"$T\":[$(for i in $(seq 1 25); do echo -n "{\"PutRequest\":{\"Item\":{\"pk\":{\"S\":\"item-$i\"},\"data\":{\"S\":\"value-$i\"}}}}"; [ $i -lt 25 ] && echo -n ","; done)]}" > /dev/null

tuts/208-lambda-list-functions/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 208-lambda-list-functions
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/208-lambda-list-functions/lambda-list-functions.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/tut.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: $REGION"
 echo "Step 1: Listing functions"; aws lambda list-functions --query 'Functions[:10].{Name:FunctionName,Runtime:Runtime,Size:CodeSize,Modified:LastModified}' --output table
 echo "Step 2: Function count by runtime"; aws lambda list-functions --query 'Functions[].Runtime' --output text | tr '\t' '\n' | sort | uniq -c | sort -rn
 echo ""; echo "Tutorial complete. Read-only."; rm -rf "$WORK_DIR"

tuts/213-ec2-security-group-audit/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 213-ec2-security-group-audit
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/213-ec2-security-group-audit/ec2-security-group-rules.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/tut.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 security groups"; aws ec2 describe-security-groups --query 'SecurityGroups[:10].{Id:GroupId,Name:GroupName,VPC:VpcId,InRules:IpPermissions|length(@),OutRules:IpPermissionsEgress|length(@)}' --output table
 echo "Step 2: Finding groups with open SSH"
 aws ec2 describe-security-groups --filters "Name=ip-permission.from-port,Values=22" "Name=ip-permission.cidr,Values=0.0.0.0/0" --query 'SecurityGroups[].{Id:GroupId,Name:GroupName}' --output table 2>/dev/null || echo "  No groups with open SSH"

tuts/215-lambda-event-invoke-config/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 215-lambda-event-invoke-config
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/215-lambda-event-invoke-config/lambda-event-invoke-config.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/tut.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 functions with event invoke configs"
 for F in $(aws lambda list-functions --query 'Functions[:5].FunctionName' --output text 2>/dev/null); do
     CONFIG=$(aws lambda get-function-event-invoke-config --function-name "$F" 2>/dev/null)

tuts/216-ec2-cost-optimization/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 216-ec2-cost-optimization
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/216-ec2-cost-optimization/ec2-cost-optimization.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 WORK_DIR=$(mktemp -d); exec > >(tee -a "$WORK_DIR/tut.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: Finding stopped instances (still incurring EBS charges)"
 aws ec2 describe-instances --filters "Name=instance-state-name,Values=stopped" --query 'Reservations[].Instances[].{Id:InstanceId,Type:InstanceType,Stopped:StateTransitionReason}' --output table 2>/dev/null || echo "  No stopped instances"
 echo "Step 2: Finding unattached EBS volumes"