mat

A modern terminal file viewer combining the best of cat, less, and grep with syntax highlighting and markdown rendering.

Features

• Syntax Highlighting - Automatic language detection with 50+ languages supported
• Markdown Rendering - Beautiful formatted output for .md files with styled headings, code blocks, lists, and more
• Grep Filtering - Filter content with regex patterns, with context lines support
• Search & Navigate - Highlight matches and jump between them with n/N
• Follow Mode - Tail files in real-time like tail -f
• Large File Support - Efficient memory-mapped loading for files >10MB
• Theme Detection - Automatically adapts to light/dark terminal themes

Installation

cargo install mat

Or build from source:

git clone https://github.com/yourusername/mat
cd mat
cargo build --release

Usage

# View a file
mat file.txt

# View with line numbers
mat -n file.txt

# Pipe from stdin
cat file.txt | mat
echo "hello world" | mat

# Force syntax highlighting language
cat config | mat -l yaml

Grep Mode

Filter to matching lines (like grep, but with context and paging):

# Show only matching lines
mat -g "pattern" file.txt

# With context lines
mat -g "error" -C 3 logfile.txt    # 3 lines before and after
mat -g "error" -B 2 -A 5 log.txt   # 2 before, 5 after

# Case insensitive
mat -g -i "warning" file.txt

# Fixed string (not regex)
mat -g -F "literal[string" file.txt

Search Mode

Highlight all matches of a pattern:

# Highlight pattern
mat -s "TODO" file.txt

# Then use n/N to jump between matches

Markdown Rendering

# Auto-detected for .md files
mat README.md

# Force markdown rendering
mat -m somefile.txt

# Disable markdown rendering
mat -M README.md

Follow Mode

Watch a file for changes (like tail -f):

mat -f /var/log/syslog

Line Selection

View specific line ranges:

mat -L 10:20 file.txt   # Lines 10-20
mat -L 50: file.txt     # Line 50 to end
mat -L :100 file.txt    # First 100 lines
mat -L 42 file.txt      # Just line 42

Keybindings

Options

Usage: mat [OPTIONS] [FILE]

Arguments:
  [FILE]  File to view (use '-' for stdin)

Options:
  -n, --line-numbers      Show line numbers
  -N, --no-highlight      Disable syntax highlighting
  -m, --markdown          Force markdown rendering
  -M, --no-markdown       Disable markdown rendering
  -f, --follow            Follow mode (like tail -f)
  -s, --search <PATTERN>  Highlight pattern matches
  -g, --grep <PATTERN>    Filter to matching lines
  -i, --ignore-case       Case-insensitive search/grep
  -F, --fixed-strings     Treat pattern as literal string
  -w, --word-regexp       Match whole words only
  -x, --line-regexp       Match whole lines only
  -A, --after <N>         Lines to show after grep match
  -B, --before <N>        Lines to show before grep match
  -C, --context <N>       Lines to show before and after match
      --wrap <MODE>       Line wrap mode: none, wrap, truncate
  -W, --max-width <N>     Max line width for truncation
  -l, --language <LANG>   Force syntax highlighting language
  -t, --theme <THEME>     Color theme (light/dark)
  -L, --lines <RANGE>     Show line range (e.g., 10:20, :50, 100:)
  -P, --no-pager          Print directly without pager
      --ansi              Preserve ANSI escape codes in input
      --force-binary      Force display of binary files
  -h, --help              Print help
  -V, --version           Print version

Highlighting

Grep vs Search

• Grep (-g): Filters the file to show only matching lines (with optional context). Matches highlighted in cyan.
• Search (-s): Shows the entire file with matches highlighted in yellow. Use n/N to navigate.

You can use both together:

mat -g "error" -s "critical" logfile.txt

Supported Languages

mat uses syntect for syntax highlighting and supports 50+ languages including:

Rust, Python, JavaScript, TypeScript, Go, C, C++, Java, Ruby, PHP, Swift, Kotlin, Scala, Haskell, Lua, Perl, R, SQL, HTML, CSS, JSON, YAML, TOML, Markdown, Bash, and many more.

License

MIT