Debug

Error tracing, log analysis, memory leak detection, HTTP debugging, and command profiling — all from the command line. Analyze log files for error patterns, parse stack traces from Python/Java/Go/JS crash dumps, monitor process memory for leaks, benchmark command execution, compare log files side-by-side, and debug HTTP endpoints with timing and SSL inspection.

Commands

trace — Find error patterns in log files

Scans a log file for error-level patterns (ERROR, FATAL, Exception, Traceback, WARN, OOM, Segfault, panic, SIGKILL, SIGSEGV). Shows match count, error breakdown by type, last 20 matching lines, and top 10 unique error patterns (with timestamps and addresses normalized for dedup).

bash scripts/script.sh trace /var/log/app.log
bash scripts/script.sh trace --pattern "OOM|Segfault|FATAL" /var/log/syslog
bash scripts/script.sh trace --last 1h /var/log/app.log
bash scripts/script.sh trace --last 2d --pattern "Exception" application.log

Options: - --pattern REGEX — Custom grep pattern (default: common error keywords) - --last 1h|30m|2d — Filter to entries within the last N hours/minutes/days

Output: Error breakdown table, last 20 matches, unique pattern summary. Exit code 1 if errors found, 0 if clean.

stacktrace — Parse and summarize stack traces

Auto-detects language (Python, Java, JavaScript, Go, C/C++), extracts the error message, and shows the call chain with file/line references. Accepts a file path or stdin (-).

bash scripts/script.sh stacktrace crash.log
cat traceback.txt | bash scripts/script.sh stacktrace -

Supported languages: Python (Traceback), Java (at ...java:N), JavaScript/TypeScript (at ...js:N), Go (goroutine), C/C++ (thread #N).

Output: Language detection, error message, call chain (with file + line), stack depth.

leaks — Monitor process memory for leaks

Samples a running process's RSS and VSZ at regular intervals, then calculates total growth. Flags possible leaks (>20% growth) or moderate growth (>5%).

bash scripts/script.sh leaks --pid 1234
bash scripts/script.sh leaks --pid 1234 --duration 60 --interval 5
bash scripts/script.sh leaks 5678

Options: - --pid PID — Process ID to monitor (required) - --duration N — Total monitoring time in seconds (default: 30) - --interval N — Sampling interval in seconds (default: 5)

Output: Time-series table (RSS, VSZ, delta), summary with start/end RSS and growth percentage.

profile — Measure command execution time

Runs a command one or more times, measures wall-clock time per run (nanosecond precision), and reports min/avg/max with a speed verdict.

bash scripts/script.sh profile "python3 slow_script.py"
bash scripts/script.sh profile --repeat 5 "curl -s https://api.example.com"
bash scripts/script.sh profile --repeat 10 "make build"

Options: - --repeat N — Number of runs (default: 1)

Output: Per-run timing, summary (avg/min/max/total), speed classification (FAST <1s, MODERATE 1-5s, SLOW >5s).

diff-logs — Compare two log files

Shows line count differences, new lines in the second file, and removed lines from the first. With --errors-only, focuses exclusively on error-level entries.

bash scripts/script.sh diff-logs before.log after.log
bash scripts/script.sh diff-logs --errors-only old.log new.log

Options: - --errors-only — Compare only error/warning lines (ERROR, FATAL, Exception, Traceback, WARN)

Output: Line count comparison, new/removed entries (up to 30/20 lines shown).

http — Debug HTTP requests

Makes a request to a URL and reports status code, redirect chain, and optionally response headers, timing breakdown (DNS, connect, TLS, first byte, total), and SSL certificate expiry.

bash scripts/script.sh http https://example.com
bash scripts/script.sh http --verbose --timing https://api.example.com/health
bash scripts/script.sh http --timing https://cdn.example.com/asset.js

Options: - --verbose — Show response headers - --timing — Show detailed timing breakdown (DNS, connect, TLS, first byte, total, size)

Output: HTTP status, SSL info (for HTTPS), redirect chain, optional headers and timing. Exit code 1 if status ≥ 400.

help — Show usage summary

bash scripts/script.sh help

Data Storage

This tool does not persist data. All output goes to stdout/stderr. Exit codes indicate success (0) or errors found (1).

Requirements

• bash 4+
• curl (for http command)
• openssl (for SSL certificate inspection in http)
• ps (for leaks command — monitors /proc via ps -p)
• grep, sed, sort, uniq, diff, wc (standard coreutils)
• date with GNU or BSD extensions (for --last time filtering in trace)
• No external dependencies — uses only standard Unix tools

When to Use

1. Production incident triage — Run trace on application logs to quickly identify error patterns and frequency during an outage
2. Crash dump analysis — Pipe a stack trace through stacktrace to auto-detect the language and extract the root cause call chain
3. Memory leak investigation — Use leaks to monitor a suspect process over time and quantify RSS growth percentage
4. Performance benchmarking — Profile build commands or API endpoints with profile --repeat to get statistically meaningful timing data
5. Deployment verification — Compare pre- and post-deploy logs with diff-logs --errors-only to catch newly introduced errors

Examples

# Trace errors in the last hour of an application log
bash scripts/script.sh trace --last 1h /var/log/myapp/error.log

# Parse a Python crash dump from clipboard
pbpaste | bash scripts/script.sh stacktrace -

# Monitor a Node.js process for memory leaks over 2 minutes
bash scripts/script.sh leaks --pid $(pgrep -f "node server.js") --duration 120 --interval 10

# Benchmark an API endpoint 10 times
bash scripts/script.sh profile --repeat 10 "curl -s https://api.myservice.com/health"

# Debug an HTTPS endpoint with full timing and headers
bash scripts/script.sh http --verbose --timing https://api.myservice.com/v2/status

---

Powered by BytesAgain | bytesagain.com | [email protected]