tabspace

A command-line tool for converting between tabs and spaces in source files. Written in F# targeting .NET 8.

Features

• Convert tabs to spaces
• Convert spaces to tabs
• Strip trailing whitespace
• Auto-detect indentation style and convert to the opposite

Building

Run directly with .NET:

dotnet run -- <file> [flags]

Build a native self-contained binary (Linux x64):

dotnet publish -r linux-x64 -p:PublishSingleFile=true -p:PublishTrimmed=true
mv bin/Release/net8.0/linux-x64/publish/tabspace .

After building, the tabspace binary can be placed anywhere on your PATH.

Usage

tabspace <file> [flags]

The file is modified in-place.

Flags

Flag	Description
-tab	Convert spaces to tabs
-space	Convert tabs to spaces
-strip	Strip trailing whitespace only
-N	Spaces per tab (e.g. -2, -4). Default: 4

Flag matching is case-insensitive and substring-based — -tabs, -totabs, -TAB all work.

Auto-detection

If no conversion flag is given, tabspace inspects the file and picks the conversion automatically:

• If most indented lines start with tabs → converts to spaces
• If most indented lines start with spaces → converts to tabs
• If counts are equal → converts to tabs

Examples

# Auto-detect and convert
tabspace main.c

# Convert tabs to 2-space indentation
tabspace main.c -space -2

# Convert spaces to tabs (4 spaces = 1 tab)
tabspace main.c -tab -4

# Strip trailing whitespace only
tabspace main.c -strip

How it works

Conversion operates line-by-line and only touches leading whitespace — the content of each line is preserved. Blank lines are left unchanged.

• Tabs → spaces: counts leading tabs, replaces them with N spaces each
• Spaces → tabs: counts leading spaces, divides by N, replaces with that many tabs
• Strip: trims trailing spaces and tabs from every non-blank line

Requirements

• .NET 8 SDK (to build)
• Linux x64 (for the prebuilt native binary target; other targets can be specified via -r)