Tag

error fix

39 posts

SSH and Networking

How to Audit SSH Logins and Failed Attempts the Safe Way

Audit SSH logins on Linux: read auth logs and the journal, count failed attempts, list successful logins by key, spot invalid users and raise the log level.

6 min read

Python

Python Subprocess Pipe Deadlock and Hanging Processes

Fix a Python subprocess that hangs: pipe buffer deadlocks with wait, missing communicate, stdin prompts, timeouts, and killing process groups.

6 min read

APIs

API Error 502 and 504 From Scripts and Proxies Fully

Understand API 502 Bad Gateway and 504 Gateway Timeout from scripts and proxies: where they come from, what to check upstream, and safe retries.

7 min read

APIs

API Error 429 Too Many Requests and Backoff in Scripts

Handle API 429 Too Many Requests in scripts: read Retry-After and rate limit headers, exponential backoff with jitter, curl retries, throttling and batching.

6 min read

Testing

Bats Error Command Not Found and Load Problems Fully

Fix Bats errors: bats command not found, load: command not found, helper libraries not found, bats-core install methods, PATH, submodules and CI setup.

6 min read

Debugging

Debugging Segfaults and Exit Codes 126 127 130 and 137

Decode shell exit codes 126, 127, 130 and 137, plus segfault status 139: what each means, how to confirm the cause and what to do about it.

6 min read

CI/CD

GitHub Actions Error Permission Denied on a Script

Fix GitHub Actions permission denied on a script: the executable bit, git update-index, shebang and line endings, noexec mounts, and how to call with bash.

6 min read

Cron and Scheduling

Cron Error Command Not Found in Crontab Causes and Fixes

Fix command not found in cron: the short PATH, tools installed in user directories, version managers, sudo, absolute paths, and how to prove the cause.

6 min read

Cron and Scheduling

Cron Job Not Running and the Seven Usual Causes Fully

Find why a cron job is not running: the daemon, the schedule, the crontab file, permissions, PATH, percent signs and output, with a numbered checklist.

6 min read