cgpt-line-endings-hygiene

name	cgpt-line-endings-hygiene
description	Detect and prevent CRLF/LF line-ending problems in Windows-origin repositories and manuscripts. Use before editing files created by RStudio, Word-adjacent tooling, PowerShell, bash, Cowork, or Codex; when Git shows every line changed; when `.gitattributes`, `core.autocrlf`, NUL bytes, carriage returns, or noisy diffs appear; or before line-ending normalization work.

CGPT Line Endings Hygiene

Use this skill to keep substantive edits separate from line-ending churn.

Pre-Edit Check

Before editing a text file you did not create:

Format-Hex -Path "path\to\file" -Count 256
git ls-files --eol -- "path/to/file"

Or, when a simple text read is enough:

$bytes = [System.IO.File]::ReadAllBytes("path\to\file")
"CRLF count: " + ([regex]::Matches([Text.Encoding]::UTF8.GetString($bytes), "`r`n")).Count
"LF count: " + ([regex]::Matches([Text.Encoding]::UTF8.GetString($bytes), "(?<!`r)`n")).Count

If the file is consistently CRLF, preserve CRLF. If it is consistently LF, preserve LF.

Decision Rule

• Existing consistent file: match its current endings.
• Newly created file: use LF unless the file type or project policy requires CRLF.
• Mixed endings: flag it. Normalize only if the user agrees or if normalization is the explicit task.
• Whole-file diff after a small edit: stop and inspect line endings before continuing.

Normalization Discipline

When normalization is needed in a Git repo:

1. Create or confirm .gitattributes.
2. Commit line-ending normalization separately from content changes.
3. Then make the substantive edit in a separate commit or separate reported change.

Minimum .gitattributes baseline:

* text=auto eol=lf
*.ps1 text eol=crlf
*.bat text eol=crlf
*.cmd text eol=crlf
*.docx binary
*.pptx binary
*.xlsx binary
*.pdf binary

Post-Edit Integrity Check

After writing:

• Confirm the diff shows only intended content changes.
• Confirm file tail and size look plausible.
• If NUL bytes, missing tail content, or unexpected byte-count changes appear, treat it as file integrity damage rather than a line-ending issue.

Rules

• Do not hide a substantive edit inside a whole-file normalization diff.
• Do not normalize delivery manuscripts or active review files midstream unless explicitly asked.
• Do not use git add --renormalize . casually in a dirty worktree.
• Pair with cgpt-onedrive-git-safety when the repo is under OneDrive or another sync root.