git stripspace

Used by hooks and editors to tidy commit messages.

🎯 What & why

Cleans up trailing whitespace and blank lines on stdin, with optional comment-stripping. Used by Git itself before storing commit messages and ideal for commit-msg hooks and editor plugins.

🧠 Mental model

A small text filter with three jobs: trim trailing spaces on every line, collapse runs of blank lines, and optionally remove or convert comment lines. Reads stdin, writes stdout, never touches files.

🛠️ Synopsis

git stripspace [-s | --strip-comments]
git stripspace [-c | --comment-lines]

🎚️ Switches & options

Flag	What it does
`-s, --strip-comments`	Remove lines beginning with the comment character (default `#`)
`-c, --comment-lines`	Prepend the comment character to every nonblank line
`(default)`	Strip trailing whitespace and collapse multiple blank lines
`(stdin/stdout)`	Always reads stdin, writes stdout - never edits files in place

💡 Use cases

Cleaning a commit message inside a commit-msg hook before Git stores it
Generating help text or notices to embed back into commit templates as comments
Normalizing pasted user input in scripts that build commit messages
Producing a tidy diff/log output from arbitrary text in shell pipelines

🧪 Examples

Tidy a commit message in a commit-msg hook

git stripspace < "$1" > "$1.tmp" && mv "$1.tmp" "$1"

Strip comment lines too

git stripspace --strip-comments < message.txt

Turn a help blurb into commented-out lines

echo 'Edit above' | git stripspace --comment-lines

Use the configured comment char

git -c core.commentChar=';' stripspace -s < message.txt

🎓 Recommendations

Wire it into your commit-msg hook; it's the cheapest way to enforce trailing-whitespace hygiene.
Honor core.commentChar by passing it through -c config rather than hardcoding #.
Use --comment-lines when generating editor instructions so they auto-strip on commit.

🪤 Common pitfalls

It does not wrap long lines or enforce subject/body separation - that's your hook's job.
--strip-comments only strips lines starting at column 0 with the comment char; indented # is preserved.
Output always ends with exactly one trailing newline; scripts expecting raw passthrough may need adjustment.

🔗 Related modules

📝 Quiz

Hit each option, then Check answers. Score is recorded; Next is always open.