Analyze Log Files

Analyze Log Files

When to Use

• When user asks to "analyze log.txt", "read the log file", "process logs", "check the logs"
• When dealing with any .log or log-related files that may contain ANSI escape sequences
• When terminal output has been captured to a file and needs analysis
• When log files appear garbled or contain escape sequence artifacts

Why This Matters

Log files captured from terminal sessions often contain ANSI escape sequences for:

• Colors (e.g., \x1b[31m for red)
• Cursor movements
• Text formatting (bold, underline)
• Screen clearing commands

These sequences make logs difficult to:

1. Read in plain text editors
2. Search with grep/​ripgrep
3. Process with text analysis tools
4. Analyze accurately by LLMs

Instructions

Step 1: Strip ANSI Escape Sequences

Before analyzing any log file, first strip the ANSI sequences using ansifilter:

ansifilter -i log.txt -o /​tmp/​clean_log.txt

For other log file names, adjust accordingly:

ansifilter -i <input_file> -o /​tmp/​clean_log.txt

Step 2: Analyze the Clean Log

Read and analyze /​tmp/​clean_log.txt instead of the original file:

# Use the Read tool on /​tmp/​clean_log.txt

Step 3: Report Findings

When reporting findings to the user:

• Reference line numbers from the clean log
• Quote relevant sections
• Summarize errors, warnings, or patterns found

Common Log File Locations

• log.txt - General purpose log in project root
• target/ - Cargo build logs
• /​tmp/​*.log - Temporary logs

Example Workflow

User: "Can you analyze log.txt and tell me what's wrong?"

1. Run: ansifilter -i log.txt -o /​tmp/​clean_log.txt
2. Read: /​tmp/​clean_log.txt
3. Analyze the content for errors, warnings, patterns
4. Report findings to user

Troubleshooting

If ansifilter is not installed:

# Ubuntu/​Debian
sudo apt-get install ansifilter

# macOS
brew install ansifilter

# Or run bootstrap.sh to install all dependencies
./​bootstrap.sh

Related Skills

• check-code-quality - For checking Rust code quality (may generate logs)
• analyze-performance - For performance analysis (generates flamegraph data)