Update orphans.sh

Author: djeada

Diff for: src/orphans.sh

@@ -1,50 +1,58 @@
 #!/usr/bin/env bash
+set -euo pipefail
 
 # Script Name: orphans.sh
-# Description: This script displays processes that might be orphans, i.e. processes that have no parent process.
-# Usage: `chmod +x orphans.sh && ./orphans.sh`
-# Example: `./orphans.sh` displays a list of processes that might be orphans.
+# Description: This script displays processes that might be orphans,
+#              i.e. processes whose parent process is not running.
+# Usage: chmod +x orphans.sh && ./orphans.sh
+# Example: ./orphans.sh  displays a list of processes that might be orphans.
 
-# Temporary files
+# Create temporary files for process data.
 TMP_FILE=$(mktemp /tmp/processes.XXXXXX)
-PPID_TMP_FILE=$(mktemp /tmp/ppid.XXXXXX)
+PIDS_TMP_FILE=$(mktemp /tmp/pids.XXXXXX)
 
-# Cleanup function
+# Cleanup function to remove temporary files.
 cleanup() {
-    rm -f "$TMP_FILE"
-    rm -f "$PPID_TMP_FILE"
+    rm -f "$TMP_FILE" "$PIDS_TMP_FILE"
 }
 
-# Error handling function
+# Error handling function.
 error_exit() {
-    echo "$1" 1>&2
+    echo "$1" >&2
     cleanup
     exit 1
 }
 
-# Function to check for orphan processes
+# Function to check for orphan processes.
 check_orphans() {
-    # Get a list of all processes' PID and PPID
-    ps -eo ppid,pid | sed 1d > "$TMP_FILE"
+    # Get a list of all processes' PPID and PID (without the header).
+    ps -eo ppid,pid --no-headers > "$TMP_FILE"
 
-    # Create a list of all parent process IDs
-    awk '{print $1}' "$TMP_FILE" | sort -u > "$PPID_TMP_FILE"
+    # Create a list of all running process IDs (PIDs) from the second column.
+    awk '{print $2}' "$TMP_FILE" | sort -u > "$PIDS_TMP_FILE"
 
-    # Check if each process has a parent process
+    # Check if each process has a parent process running.
     while read -r ppid pid; do
-        if ! grep -q -w "^$ppid$" "$PPID_TMP_FILE"; then
-            echo "Process $pid might be an orphan"
+        # Skip kernel or system processes with parent PID 0.
+        if [ "$ppid" -eq 0 ]; then
+            continue
+        fi
+
+        # If the parent's PID is not in the list of running PIDs,
+        # then the process might be orphaned.
+        if ! grep -q -w "^$ppid$" "$PIDS_TMP_FILE"; then
+            echo "Process $pid might be an orphan (parent PID: $ppid not found)"
         fi
     done < "$TMP_FILE"
 }
 
-# Check if the temp files were created
-if [[ ! -e "$TMP_FILE" || ! -e "$PPID_TMP_FILE" ]]; then
+# Ensure that temporary files were created.
+if [[ ! -e "$TMP_FILE" || ! -e "$PIDS_TMP_FILE" ]]; then
     error_exit "Failed to create temporary file. Make sure you have the right permissions."
 fi
 
-# Set a trap for cleanup
+# Set a trap to cleanup temporary files on exit.
 trap cleanup EXIT
 
-# Run the main function
+# Run the orphan-check function.
 check_orphans