git-loc

Generate a per-language lines of code time series for a Git repository without checking out each commit.

This tool walks the linear history of a branch/ref, computes a tree diff at each commit, and updates running totals using git blob contents + tokei for language detection and counting.

• Uses tokei for language detection and for code / comments / blanks counts (including embedded-language blobs).
• Avoids expensive checkouts: reads blobs directly from the Git object database.
• Caches per-blob tokei results in-memory, so identical blobs are only counted once per run.
• Optional SVG plot of the top languages over time.

Note: “lines of code” usually refers to the code column (non-blank, non-comment lines). The CSV also includes comments, blanks, and lines = code+comments+blanks.

Install

From crates.io

cargo install git-loc

From source

git clone https://github.com/banteg/git-loc.git
cd git-loc
cargo install --path .

Usage

Emit CSV (stdout)

git-loc --repo .

Emit CSV + SVG plot

git-loc --repo . --out loc.csv --plot loc.svg

Plot options

# Use code/comments/blanks/lines for the plot metric
git-loc --repo . --out loc.csv --plot loc.svg --plot-metric code

# Plot top 5 languages
git-loc --repo . --out loc.csv --plot loc.svg --plot-top 5

# Show git tags on the plot
git-loc --repo . --out loc.csv --plot loc.svg --plot-tags

# Only include selected languages (repeatable or comma-separated)
git-loc --repo . --out loc.csv --plot loc.svg --only Python --only "Jinja2"
git-loc --repo . --out loc.csv --plot loc.svg --only Python,Jinja2

Only count a subdirectory

git-loc --repo . --subdir src --out loc.csv --plot loc.svg

Disable the progress bar

git-loc --repo . --no-progress

Output format

The CSV is long-form: one row per (commit, language).

Columns:

• commit: commit SHA
• timestamp: commit time (unix seconds)
• datetime: commit time
• language: language name (as reported by tokei)
• code: code lines
• comments: comment lines
• blanks: blank lines
• lines: code + comments + blanks

This long format is convenient for plotting.

Plot

--plot <path.svg> writes an SVG chart of the top languages ranked by totals at the final commit.

Plot-related flags:

• --plot-metric code|lines|comments|blanks (default: code)
• --plot-top N (default: 8)
• --plot-tags shows git tags on the plot
• --only <LANG> repeatable or comma-separated
• --no-progress disables the progress bar on stderr

How it works

1. Resolve --rev (default HEAD).
2. Build the first-parent chain from root → tip.
3. For each commit:
   • Diff parent_tree → commit_tree
   • For each changed file:
     • If the old blob exists: subtract its cached per-language tokei counts
     • If the new blob exists: add its cached per-language tokei counts
4. Emit the current per-language totals (and optionally add a plot point).

Counting is done by writing blob bytes to a temporary file (with the original basename so tokei’s path-based detection works), then calling tokei as a library.