Find diff lines

find_diff_lines.sh

#!/bin/bash

# Check number of arguments
if [ $# -ne 3 ]; then
    echo "Usage: $0 <file1> <file2> <output_file>"
    echo "Example: $0 file1.txt file2.txt differences.txt"
    exit 1
fi

# Get command line arguments
FILE1="$1"
FILE2="$2"
OUTPUT="$3"

# Check if input 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

# Create temporary directory
TEMP_DIR=$(mktemp -d)
FILE1_SORTED="$TEMP_DIR/file1_sorted.txt"
FILE2_SORTED="$TEMP_DIR/file2_sorted.txt"
FILE1_UNIQUE="$TEMP_DIR/file1_unique.txt"
FILE2_UNIQUE="$TEMP_DIR/file2_unique.txt"

# Cleanup function
cleanup() {
    rm -rf "$TEMP_DIR"
}

# Set cleanup on exit
trap cleanup EXIT

# Sort files (comm requires sorted input)
sort "$FILE1" -o "$FILE1_SORTED"
sort "$FILE2" -o "$FILE2_SORTED"

# Find lines unique to file1
comm -23 "$FILE1_SORTED" "$FILE2_SORTED" > "$FILE1_UNIQUE"

# Find lines unique to file2
comm -13 "$FILE1_SORTED" "$FILE2_SORTED" > "$FILE2_UNIQUE"

# Combine all different lines to output file
cat "$FILE1_UNIQUE" "$FILE2_UNIQUE" > "$OUTPUT"

echo "Differences saved to: $OUTPUT"