bash markdown preview tool

mdview

#!/usr/bin/env bash

# save to ~/bin/mdview:
# gh gist view 13fefaade768ab04167d012f74bbab7a --raw > ~/bin/mdview && chmod +x ~/bin/mdview

# mdview - Preview markdown files with gh markdown-preview --dark-mode
# Usage: mdview [OPTIONS] [file|directory]
# Options:
#   -h, --help            Show this help message
#   -r, --recurse-dirs    Recursively search for markdown files in subdirectories
#
# Dependencies (brew install <name> if missing):
#   - gh          GitHub CLI (brew install gh)
#   - gh extension: yusukebe/gh-markdown-preview (gh extension install yusukebe/gh-markdown-preview)
#   - fzf         Fuzzy finder for multi-file selection (brew install fzf)
#
# gh must be authenticated: gh auth login

set -euo pipefail

show_help() {
    cat <<EOF
Usage: mdview [OPTIONS] [file|directory]

Preview markdown files using GitHub's markdown-preview extension.

OPTIONS:
  -h, --help            Show this help message
  -r, --recurse-dirs    Recursively search for markdown files in subdirectories

EXAMPLES:
  mdview file.md                    # Preview a specific file
  mdview                            # Preview markdown files in current directory
  mdview ~/projects                 # Preview markdown files in a directory
  mdview -r ~/projects              # Recursively search for markdown files
EOF
}

check_deps() {
    local missing=()

    if ! command -v gh &>/dev/null; then
        missing+=("gh")
    fi
    if ! command -v fzf &>/dev/null; then
        missing+=("fzf")
    fi

    if [[ ${#missing[@]} -gt 0 ]]; then
        echo "Missing dependencies. Install:"
        for dep in "${missing[@]}"; do
            echo "  brew install $dep"
        done
        exit 1
    fi

    if ! gh auth status &>/dev/null; then
        echo "gh CLI not authenticated. Run: gh auth login"
        exit 1
    fi

    if ! gh extension list | grep -q "markdown-preview"; then
        echo "Missing gh extension. Install:"
        echo "  gh extension install yusukebe/gh-markdown-preview"
        exit 1
    fi
}

open_preview() {
    local file="$1"
    local full_path
    full_path=$(cd "$(dirname "$file")" && pwd)/$(basename "$file")
    echo "✓ Opening: $full_path"
    echo
    gh markdown-preview --dark-mode "$file"
}

target="."
recurse=false

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
    -h | --help)
        show_help
        exit 0
        ;;
    -r | --recurse-dirs)
        recurse=true
        shift
        ;;
    *)
        target="$1"
        shift
        ;;
    esac
done

check_deps

# If target is a file, preview it directly
if [[ -f "$target" ]]; then
    open_preview "$target"
    exit 0
fi

# If target is a directory, use fzf to select a markdown file
if [[ -d "$target" ]]; then
    markdown_files=()
    if [[ "$recurse" == true ]]; then
        while IFS= read -r f; do markdown_files+=("$f"); done < <(find "$target" -name "*.md" -type f | sort)
    else
        while IFS= read -r f; do markdown_files+=("$f"); done < <(find "$target" -maxdepth 1 -name "*.md" -type f | sort)
    fi

    if [[ ${#markdown_files[@]} -eq 0 ]]; then
        echo "No markdown files found in '$target'"
        exit 1
    fi

    # If only one file found, open it directly
    if [[ ${#markdown_files[@]} -eq 1 ]]; then
        open_preview "${markdown_files[0]}"
        exit 0
    fi

    # Multiple files: use fzf to select
    selected=$(printf '%s\n' "${markdown_files[@]}" | fzf --prompt "Select markdown file: ")
    if [[ -n "$selected" ]]; then
        open_preview "$selected"
    else
        echo "No markdown file selected"
        exit 1
    fi
    exit 0
fi

echo "Error: '$target' is neither a file nor a directory"
exit 1