.log file
Web & DevelopmentLOG is a suffix for records, not a universal format. Logs may be text, JSON or proprietary binary data. Inspect the failure time and surrounding entries, then redact private details before sharing.
- What it is used for
- Records of processing, warnings and errors
- What the file contains
- Producer-dependent
All sections, questions and sources
Content reviewed： · Editor：Kai
Opening steps
Choose your environment or purpose to see its steps.
Menu labels and support vary by app, OS and version. Preserve the original before making changes.
Troubleshooting by symptom
- Unreadable bytes: identify binary/compressed logs and use the proper viewer.
- Too large: export a relevant time range or use a large-file editor.
- Unclear cause: compare surrounding events and time zones, not just the final line.
- Earlier period missing: inspect rotated/compressed logs and retention.
- Time mismatch: check UTC/local time and clock differences.
- Error search is insufficient: inspect preceding warnings, actions and connections.
LOG → support excerpt
- Copy relevant entries with enough surrounding context.
- Redact email addresses, tokens and device details; retain the original separately.
- When tabulating logs, verify timestamps, severity and multiline messages are preserved.
Editing may remove diagnostic evidence; separate public excerpts from originals.
Finding the first failure
Later errors can cascade from an earlier failure. Trace actions and responses starting before the incident.
Correlate time, severity, process and identifiers when multiple operations share a log.
Source for these steps：Python Software Foundation · Logging HOWTO
Log retention and sharing
Rotation can split or compress logs; retain the set covering the investigation period.
Preserve the original and redact the sharing copy; establish whether redacted fields are needed for diagnosis.
Source for these steps：Python Software Foundation · Logging HOWTO
Related-format differences
| Format | Main role | Selection notes |
|---|---|---|
| LOG | Application records | Inspect format and timestamps |
| TXT | General text | Meaning depends on content |
| GZ | Compressed logs / data | Inspect the decompressed format |
Handling and security
Logs may contain credentials and activity history. Do not publish originals or delete active logs casually.
Questions and answers
Are all logs text?
No; proprietary and compressed formats also exist.
Is one error line enough?
Surrounding events and timestamps may be needed.
Will deleting a log fix the issue?
Removing records does not generally fix their cause.
May I delete LOG files?
Follow the application’s retention/deletion process and establish the purpose of diagnostic/audit records.
Is every LOG plain text?
Some producers use proprietary formats; consult the dedicated tool if it is not readable text.
Format facts: name, steward and MIME type
- Formal name
- Application or system log
- Steward / specification
- Producing application
- MIME type
- Depends on the producer or server; an extension alone does not establish a MIME type.
Primary and official sources
- Project documentationLogging HOWTO
Reference for log levels, output and encoding.
Python Software Foundation · Link checked： - Project documentationDatabase File Format
Documents SQLite headers and companion journals.
SQLite Project · Link checked：