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/197-ec2-describe-instances/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 197-ec2-describe-instances
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/197-ec2-describe-instances/ec2-describe-instances.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: $REGION"
 echo "Step 1: Listing all instances"; aws ec2 describe-instances --query 'Reservations[].Instances[].{Id:InstanceId,Type:InstanceType,State:State.Name,Name:Tags[?Key==`Name`].Value|[0]}' --output table 2>/dev/null || echo "  No instances"
 echo "Step 2: Counting by state"; aws ec2 describe-instances --query 'Reservations[].Instances[].State.Name' --output text | tr '\t' '\n' | sort | uniq -c
 echo ""; echo "Tutorial complete. Read-only."; rm -rf "$WORK_DIR"

tuts/200-ec2-vpc-subnets/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 200-ec2-vpc-subnets
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/200-ec2-vpc-subnets/ec2-vpc-subnets.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 VPCs"; aws ec2 describe-vpcs --query 'Vpcs[].{Id:VpcId,CIDR:CidrBlock,Default:IsDefault}' --output table
 echo "Step 2: Listing subnets"; aws ec2 describe-subnets --query 'Subnets[:10].{Id:SubnetId,VPC:VpcId,AZ:AvailabilityZone,CIDR:CidrBlock}' --output table
 echo "Step 3: Listing route tables"; aws ec2 describe-route-tables --query 'RouteTables[:5].{Id:RouteTableId,VPC:VpcId,Routes:Routes|length(@)}' --output table

tuts/201-lambda-logging/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 201-lambda-logging
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/201-lambda-logging/lambda-logging.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: $REGION"
 echo "Step 1: Listing Lambda log groups"; aws logs describe-log-groups --log-group-name-prefix /aws/lambda --query 'logGroups[:10].{Name:logGroupName,Stored:storedBytes,Retention:retentionInDays}' --output table
 echo "Step 2: Getting recent log events from a function"
 LG=$(aws logs describe-log-groups --log-group-name-prefix /aws/lambda --query 'logGroups[0].logGroupName' --output text 2>/dev/null)

tuts/204-ec2-network-interfaces/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 204-ec2-network-interfaces
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/204-ec2-network-interfaces/ec2-network-interfaces.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: $REGION"
 echo "Step 1: Listing network interfaces"; aws ec2 describe-network-interfaces --query 'NetworkInterfaces[:10].{Id:NetworkInterfaceId,Type:InterfaceType,Status:Status,SubnetId:SubnetId}' --output table
 echo "Step 2: Counting by type"; aws ec2 describe-network-interfaces --query 'NetworkInterfaces[].InterfaceType' --output text | tr '\t' '\n' | sort | uniq -c | sort -rn
 echo ""; echo "Tutorial complete. Read-only."; rm -rf "$WORK_DIR"

tuts/207-ec2-volumes/REVISION-HISTORY.md

@@ -0,0 +1,8 @@
+# Revision History: 207-ec2-volumes
+
+## Shell (CLI script)
+
+### 2026-04-14 v1 published
+- Type: functional
+- Initial version
+

tuts/207-ec2-volumes/ec2-volumes.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 volumes"; aws ec2 describe-volumes --query 'Volumes[:10].{Id:VolumeId,Type:VolumeType,Size:Size,State:State,AZ:AvailabilityZone}' --output table
 echo "Step 2: Volume summary"; echo "  Total: $(aws ec2 describe-volumes --query 'Volumes | length(@)' --output text) volumes"
 echo ""; echo "Tutorial complete. Read-only."; rm -rf "$WORK_DIR"