feat: add utils directory with diff-files.sh script

Author: joshjohanning

utils/README.md

@@ -0,0 +1,7 @@
+# utils
+
+These are designed to be miscellaneous utility scripts that don't fit into other categories.
+
+## diff-files.sh
+
+Compare and display the differences between two files

utils/diff-files.sh

@@ -0,0 +1,104 @@
+#!/bin/bash
+
+# diff-files.sh - Find differences between two files
+# 
+# Usage: 
+#   ./diff-files.sh file1 file2                    # Compare two files (output to stdout)
+#   ./diff-files.sh file1 file2 --output diff.txt  # Save output to file
+#   ./diff-files.sh file1 file2 | grep "+"         # Pipe output to other commands
+#   ./diff-files.sh --help                         # Show this help
+#
+# The script outputs the diff to stdout by default for maximum flexibility
+
+set -e
+
+# Function to show usage
+show_usage() {
+  echo "Usage: $0 <file1> <file2> [options]"
+  echo ""
+  echo "Options:"
+  echo "  --output FILE    Save output to specified file instead of stdout"
+  echo "  --help           Show this help message"
+  echo ""
+  echo "Examples:"
+  echo "  $0 old.txt new.txt                    # Output to stdout"
+  echo "  $0 old.txt new.txt --output diff.txt  # Save to file"
+  echo "  $0 old.txt new.txt | grep \"+\"         # Pipe to other commands"
+}
+
+
+
+# Parse arguments
+OUTPUT_FILE=""
+FILE1=""
+FILE2=""
+
+while [[ $# -gt 0 ]]; do
+  case $1 in
+    --output)
+      OUTPUT_FILE="$2"
+      shift 2
+      ;;
+    --help|-h)
+      show_usage
+      exit 0
+      ;;
+    *)
+      if [[ -z "$FILE1" ]]; then
+        FILE1="$1"
+      elif [[ -z "$FILE2" ]]; then
+        FILE2="$1"
+      else
+        echo "Error: Too many arguments"
+        show_usage
+        exit 1
+      fi
+      shift
+      ;;
+  esac
+done
+
+# Check if we have both files
+if [[ -z "$FILE1" ]] || [[ -z "$FILE2" ]]; then
+  echo "Error: Please provide two files to compare"
+  echo ""
+  show_usage
+  exit 1
+fi
+
+# Check if files exist
+if [[ ! -f "$FILE1" ]]; then
+  echo "Error: File '$FILE1' does not exist"
+  exit 1
+fi
+
+if [[ ! -f "$FILE2" ]]; then
+  echo "Error: File '$FILE2' does not exist"
+  exit 1
+fi
+
+# Generate diff and extract only the actual differences (+ and - lines)
+DIFF_OUTPUT=$(diff -u "$FILE1" "$FILE2" 2>/dev/null || true)
+
+# Check if files are identical
+if [[ -z "$DIFF_OUTPUT" ]]; then
+  echo "No differences found." >&2
+else
+  # Filter to only show lines that were added (+) or removed (-)
+  # Skip the header lines (---, +++, @@)
+  FILTERED_DIFF=$(echo "$DIFF_OUTPUT" | grep -E "^[+-][^+-]")
+  
+  if [[ -n "$FILTERED_DIFF" ]]; then
+    LINE_COUNT=$(echo "$FILTERED_DIFF" | wc -l | tr -d ' ')
+    
+    if [[ -n "$OUTPUT_FILE" ]]; then
+      echo "$FILTERED_DIFF" > "$OUTPUT_FILE"
+      echo "Saved $LINE_COUNT lines of differences to $OUTPUT_FILE" >&2
+    else
+      echo "$FILTERED_DIFF"
+      echo "Found $LINE_COUNT lines of differences" >&2
+    fi
+  else
+    echo "No content differences found." >&2
+  fi
+fi