strip_tags

Strip HTML tags from files or stdin while preserving text content.

Available in two versions with identical CLI interfaces:

• strip_tags - Python + BeautifulSoup (robust, handles edge cases)
• strip_tags.bash - Pure Bash + sed (fast, portable, no dependencies)

Quick Start

# Strip all HTML tags
echo "<p>Hello <b>world</b></p>" | strip_tags
# Output: Hello world

# Preserve specific tags
echo "<p>Hello <b>world</b></p>" | strip_tags -a b
# Output: Hello <b>world</b>

# Process a file
strip_tags index.html > clean.txt

# Pipe from curl
curl -s https://example.com | strip_tags -a h1,p

Features

• Remove HTML tags while preserving text content
• Selectively preserve tags with -a/--allow
• Automatic whitespace normalization (collapse multiple blank lines)
• Process files or piped stdin
• Bash tab completion for options and common HTML tags
• Full Unicode support

Installation

Requirements

• Python version: Python 3.10+ and BeautifulSoup4
• Bash version: Bash 5.2+ and GNU sed (no other dependencies)

User Install

git clone https://github.com/Open-Technology-Foundation/strip_tags.git && cd strip_tags && make install

System Install

git clone https://github.com/Open-Technology-Foundation/strip_tags.git && cd strip_tags && sudo make install PREFIX=/usr/local

Optional: pre-build Python venv with make install-venv

Development (Symlink Only)

For development, create symlinks without copying files:

make link
# Or for system-wide: sudo make link BINDIR=/usr/local/bin

Update

Pull latest changes and refresh symlinks:

make update

Uninstall

make uninstall
# Or: sudo make uninstall PREFIX=/usr/local

Tab Completion

Add to ~/.bashrc:

source ~/.local/share/yatti/strip_tags/.bash_completion
# Or for system install: source /usr/local/share/yatti/strip_tags/.bash_completion

Usage

strip_tags [OPTIONS] [FILE]

Options:
  -a, --allow TAGS   Comma-separated list of tags to preserve
  --no-squeeze       Disable collapsing of repeated blank lines
  -v, --version      Show version and exit
  -h, --help         Show this help and exit

Examples

Basic Tag Stripping

# From stdin
echo "<div><p>Text</p></div>" | strip_tags

# From file
strip_tags document.html

# Save output
strip_tags document.html > clean.txt

Preserve Specific Tags

# Keep bold tags
strip_tags -a b < input.html

# Keep multiple tags (comma-separated)
strip_tags --allow "a,p,h1,h2,h3" page.html

# Spaces allowed around commas
strip_tags -a "p, div, span" page.html

# Namespaced tags (SVG, etc.)
strip_tags -a "svg:rect,svg:circle" drawing.svg

Pipeline Usage

# Fetch and clean a webpage
curl -s https://example.com | strip_tags -a p,h1

# Extract text from HTML email
cat email.html | strip_tags | less

# Clean multiple files
for f in *.html; do strip_tags "$f" > "${f%.html}.txt"; done

Whitespace Control

# Default: collapse 3+ blank lines to 2
strip_tags document.html

# Preserve all whitespace
strip_tags --no-squeeze document.html

Performance

Tested on 33KB real-world HTML (averaged over 5 runs):

Scenario	Python	Bash	Speedup
Simple tags	57 ms	10 ms	5.5x
With --allow	58 ms	13 ms	4.5x
33KB HTML	68 ms	18 ms	3.8x
33KB + allow	66 ms	59 ms	1.1x

Bash is 4-5x faster for typical use cases due to lower startup overhead.

Accuracy

Feature	Python	Bash	Notes
Basic HTML	100%	100%	Identical output
Nested tags	100%	100%	Both handle correctly
Multi-line tags	Yes	Yes	Tags spanning lines
Self-closing	Yes	Yes	<br/>, <hr/>
Namespaced tags	Yes	Yes	svg:rect, xlink:href
Script blocks	Preserves content	Removes entirely	Different by design
Style blocks	Preserves content	Removes entirely	Different by design
HTML comments	Preserves	Removes
DOCTYPE	Preserves	Removes
> in attributes	Handles	Breaks	Known Bash limitation
Malformed HTML	Robust recovery	Best-effort	Python more forgiving
HTML entities	Decodes some	Preserves as-is

When to Use Which

Use Python (strip_tags) when:

• Processing malformed or complex HTML
• You need script/style content preserved (not removed)
• Accuracy is more important than speed
• HTML contains > inside attribute values

Use Bash (strip_tags.bash) when:

• Speed is priority (4-5x faster)
• You want script/style blocks fully removed
• Running on minimal systems without Python
• Processing clean, well-formed HTML
• In containers or constrained environments

Testing

Run the full test suite (111 tests):

source .venv/bin/activate
pytest tests/ -v

Run specific test modules:

# Python tests only (65 tests)
pytest tests/test_python_strip_tags.py -v

# Bash tests only (46 tests)
pytest tests/test_bash_strip_tags.py -v

Run performance comparison:

python tests/performance_matrix.py

License

GPL-3.0