请求编写Shell脚本：检测文件名是否含时间戳并按需追加

Got it, let's build a shell script that handles checking for an existing timestamp in a filename and appending one if it's missing. I'll use a common timestamp format (YYYYMMDD_HHMMSS) as an example—you can tweak this to match your preferred format easily.

The Script #

Here's a complete, commented script that does exactly what you need:

#!/bin/bash

# Optional: Accept target file as a command-line argument (uncomment below)
# if [ $# -eq 0 ]; then
#     echo "Usage: $0 <target-file>"
#     exit 1
# fi
# target_file="$1"

# Define your target file (replace with your actual filename)
target_file="document.pdf"

# Define the timestamp format we want to use (adjust as needed)
timestamp=$(date +"%Y%m%d_%H%M%S")

# Regex pattern to detect the timestamp at the end of the filename
# This matches "_YYYYMMDD_HHMMSS" before the extension (if any)
timestamp_pattern="_[0-9]{8}_[0-9]{6}(\.[a-zA-Z0-9]+)?$"

# Check if the filename already contains a valid timestamp
if [[ "$target_file" =~ $timestamp_pattern ]]; then
    echo "✅ File '$target_file' already has a timestamp. Moving to next steps..."
    
    # Add your post-check logic here
    # Example: Upload to cloud storage, process the file, etc.
    # aws s3 cp "$target_file" s3://my-bucket/processed/
else
    echo "⚠️ No timestamp found in '$target_file'. Appending one now..."
    
    # Split filename into base name and extension (handles files without extensions)
    file_base="${target_file%.*}"
    file_ext="${target_file#*.}"
    
    # Construct the new filename
    if [[ "$file_base" == "$file_ext" ]]; then
        # No extension case (e.g., "README")
        new_filename="${file_base}_${timestamp}"
    else
        # With extension case (e.g., "document.pdf" → "document_20240520_143022.pdf")
        new_filename="${file_base}_${timestamp}.${file_ext}"
    fi
    
    # Rename the file
    mv "$target_file" "$new_filename"
    echo "✅ Successfully renamed to '$new_filename'"
    
    # Add your post-rename logic here (use new_filename instead of target_file)
    # Example: Compress the file
    # gzip "$new_filename"
fi

Key Details to Note #

• Timestamp Format: The date +"%Y%m%d_%H%M%S" command generates a timestamp like 20240520_143022. Change the format string (e.g., %Y-%m-%d for 2024-05-20) if you need a different style.
• Regex Pattern: The timestamp_pattern is tailored to match our example format. If you change the timestamp format, update the regex to match—for example, if using hyphens, adjust the pattern to -[0-9]{4}-[0-9]{2}-[0-9]{2}.
• Command-Line Argument: Uncomment the top section to make the script accept a filename as an input parameter (e.g., ./timestamp_script.sh report.txt), which makes it more reusable.
• No Extension Handling: The script correctly handles files without extensions (like README) by appending the timestamp directly to the base name.

Testing the Script #

1. Save the script as timestamp_checker.sh
2. Make it executable: chmod +x timestamp_checker.sh
3. Run it: ./timestamp_checker.sh (or pass a filename if you enabled the argument option)

内容的提问来源于stack exchange，提问作者awareness_seeker