Add robustness improvements: bash version check, cleanup trap, hostname sanitization, parallel job limit

- Add bash 4.2+ version check since script uses declare -g -A
- Add cleanup trap (EXIT/INT/TERM) for SMART_CACHE_DIR temp directory
- Sanitize hostname to strip unexpected characters
- Limit parallel SMART collection to 10 concurrent jobs

Fixes #25

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

driveAtlas.sh

@@ -11,8 +11,25 @@
 # Note: Not using -u (nounset) as script uses ${var:-default} patterns
 set -o pipefail
 
+# Require bash 4.2+ for declare -g -A (global associative arrays)
+if ((BASH_VERSINFO[0] < 4 || (BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] < 2))); then
+    echo "ERROR: This script requires Bash 4.2 or higher (current: $BASH_VERSION)" >&2
+    exit 1
+fi
+
 VERSION="1.1.0"
 
+#------------------------------------------------------------------------------
+# Cleanup Trap
+# Ensures temporary directories are removed on exit or interruption
+#------------------------------------------------------------------------------
+cleanup() {
+    if [[ -n "${SMART_CACHE_DIR:-}" && -d "$SMART_CACHE_DIR" ]]; then
+        rm -rf "$SMART_CACHE_DIR"
+    fi
+}
+trap cleanup EXIT INT TERM
+
 #------------------------------------------------------------------------------
 # Path Constants
 # Centralized path definitions to avoid hardcoding throughout the script
@@ -607,7 +624,7 @@ get_storage_controllers() {
 #     Values: PCI path strings (for --show-pci option)
 #------------------------------------------------------------------------------
 build_drive_map() {
-    local host="$(hostname)"
+    local host="$(hostname | tr -cd '[:alnum:]-_.')"
     local mapping="${SERVER_MAPPINGS[$host]}"
 
     # Declare global arrays directly
@@ -886,7 +903,7 @@ get_drive_smart_info() {
 # Main Display Logic
 #------------------------------------------------------------------------------
 
-HOSTNAME=$(hostname)
+HOSTNAME=$(hostname | tr -cd '[:alnum:]-_.')
 CHASSIS_TYPE=${CHASSIS_TYPES[$HOSTNAME]:-"unknown"}
 
 # Display chassis layout
@@ -977,15 +994,22 @@ if [[ "$SKIP_SMART" != true ]]; then
     SMART_CACHE_DIR="$(mktemp -d)"
     log_info "Collecting SMART data in parallel..."
 
+    local max_parallel_jobs=10
+    local job_count=0
     for bay in $all_bays; do
         device="${DRIVE_MAP[$bay]}"
         if [[ -n "$device" && "$device" != "EMPTY" && -b "/dev/$device" ]]; then
             # Launch background job to collect raw smartctl data
             (sudo smartctl -A -i -H "/dev/$device" > "$SMART_CACHE_DIR/${device}.raw" 2>/dev/null) &
+            ((job_count++))
+            if ((job_count >= max_parallel_jobs)); then
+                wait -n 2>/dev/null || wait  # wait -n requires bash 4.3+, fall back to wait
+                ((job_count--))
+            fi
         fi
     done
 
-    # Wait for all background SMART queries to complete
+    # Wait for all remaining background SMART queries to complete
     wait
     log_info "SMART data collection complete"
 fi
@@ -1078,11 +1102,6 @@ for bay in $all_bays; do
     fi
 done
 
-# Clean up SMART cache directory
-if [[ -n "${SMART_CACHE_DIR:-}" && -d "$SMART_CACHE_DIR" ]]; then
-    rm -rf "$SMART_CACHE_DIR"
-fi
-
 # NVMe drives (only show unmapped ones - mapped NVMe drives appear in main table)
 nvme_devices=$(lsblk -d -n -o NAME,SIZE | grep "^nvme" 2>/dev/null)
 if [[ -n "$nvme_devices" ]]; then