browser-cat

A Rust port of bcat by Ryan Tomayko — pipe text or HTML to your browser from the command line.

# plain text
echo "hello world" | browser-cat

# ANSI colours
cargo build 2>&1 | browser-cat --ansi

# an HTML file
browser-cat index.html

# a command's output
browser-cat --command -- make docs

Binaries

Binary	Description
`browser-cat`	Main utility — opens a browser window and streams output into it
`a2h`	Standalone ANSI-to-HTML filter, writes to stdout

Options

Usage: browser-cat [OPTIONS] [FILE]...

Options:
  -H, --html              Input is already HTML (passthrough)
  -t, --text              Input is plain text (wrap in <pre>)
  -b, --browser <BROWSER> Open this browser instead of the system default
  -T, --title <TEXT>      Browser window title
  -a, --ansi              Convert ANSI escape sequences to HTML
  -p, --persist           Keep server running after browser closes (allow reload)
  -c, --command           Treat arguments as a command to run; read its stdout
  -d, --debug             Verbose debug logging to stderr
  -h, --help              Print help

The browser can also be set via the BCAT_BROWSER environment variable.

btee mode

Symlink (or copy) the binary as btee and it will tee raw input to stdout while also opening a browser window — useful for watching long-running builds:

ln -s browser-cat btee
make 2>&1 | btee | grep error

Format detection

If no format flag is given, browser-cat sniffs the first chunk of input: if the first non-whitespace character is < it is treated as HTML, otherwise as plain text wrapped in <pre>.

Building

cargo build --release
# binaries land in target/release/browser-cat and target/release/a2h

Requires Rust 1.80+ (uses OnceLock and axum 0.8).

Credits

Based on bcat by Ryan Tomayko, originally written in Ruby. See LICENSE for copyright details.