Configure Linux text editors with vim and nano for system administration

#!/usr/bin/env bash

set -euo pipefail

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Script variables
SCRIPT_NAME="$(basename "$0")"
BACKUP_DIR="/tmp/editor-config-backup-$(date +%Y%m%d-%H%M%S)"

# Usage function
usage() {
    echo "Usage: $SCRIPT_NAME [OPTIONS]"
    echo "Configure vim and nano editors for system administration"
    echo ""
    echo "Options:"
    echo "  -e, --editor EDITOR    Set default editor (vim|nano) [default: vim]"
    echo "  -u, --user USER       Configure for specific user [default: current user]"
    echo "  -h, --help           Show this help message"
    echo ""
    echo "Example: $SCRIPT_NAME --editor vim --user admin"
}

# Default values
DEFAULT_EDITOR="vim"
TARGET_USER="${SUDO_USER:-$USER}"

# Parse arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        -e|--editor)
            DEFAULT_EDITOR="$2"
            if [[ "$DEFAULT_EDITOR" != "vim" && "$DEFAULT_EDITOR" != "nano" ]]; then
                echo -e "${RED}Error: Editor must be 'vim' or 'nano'${NC}" >&2
                exit 1
            fi
            shift 2
            ;;
        -u|--user)
            TARGET_USER="$2"
            shift 2
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        *)
            echo -e "${RED}Error: Unknown option $1${NC}" >&2
            usage
            exit 1
            ;;
    esac
done

# Cleanup function
cleanup() {
    if [[ -d "$BACKUP_DIR" ]]; then
        echo -e "${YELLOW}Cleaning up backup directory: $BACKUP_DIR${NC}"
        rm -rf "$BACKUP_DIR"
    fi
}

# Error handler
error_handler() {
    echo -e "${RED}Error occurred on line $1. Attempting rollback...${NC}" >&2
    if [[ -d "$BACKUP_DIR" ]]; then
        echo -e "${YELLOW}Restoring from backup: $BACKUP_DIR${NC}"
        if [[ -f "$BACKUP_DIR/.vimrc" ]]; then
            cp "$BACKUP_DIR/.vimrc" "/home/$TARGET_USER/.vimrc" 2>/dev/null || true
        fi
        if [[ -f "$BACKUP_DIR/.nanorc" ]]; then
            cp "$BACKUP_DIR/.nanorc" "/home/$TARGET_USER/.nanorc" 2>/dev/null || true
        fi
        if [[ -f "$BACKUP_DIR/.bashrc" ]]; then
            cp "$BACKUP_DIR/.bashrc" "/home/$TARGET_USER/.bashrc" 2>/dev/null || true
        fi
    fi
    cleanup
    exit 1
}

trap 'error_handler $LINENO' ERR
trap cleanup EXIT

# Check prerequisites
echo -e "${BLUE}[1/8] Checking prerequisites...${NC}"
if [[ $EUID -ne 0 ]]; then
    echo -e "${RED}Error: This script must be run as root or with sudo${NC}" >&2
    exit 1
fi

if ! id "$TARGET_USER" &>/dev/null; then
    echo -e "${RED}Error: User '$TARGET_USER' does not exist${NC}" >&2
    exit 1
fi

# Auto-detect distribution
echo -e "${BLUE}[2/8] Detecting distribution...${NC}"
if [[ ! -f /etc/os-release ]]; then
    echo -e "${RED}Error: Cannot detect distribution - /etc/os-release not found${NC}" >&2
    exit 1
fi

. /etc/os-release

case "$ID" in
    ubuntu|debian)
        PKG_MGR="apt"
        PKG_UPDATE="apt update -y"
        PKG_INSTALL="apt install -y"
        PKG_UPGRADE="apt upgrade -y"
        ;;
    almalinux|rocky|centos|rhel|ol)
        PKG_MGR="dnf"
        PKG_UPDATE="dnf update -y"
        PKG_INSTALL="dnf install -y"
        PKG_UPGRADE="dnf upgrade -y"
        ;;
    fedora)
        PKG_MGR="dnf"
        PKG_UPDATE="dnf update -y"
        PKG_INSTALL="dnf install -y"
        PKG_UPGRADE="dnf upgrade -y"
        ;;
    amzn)
        PKG_MGR="yum"
        PKG_UPDATE="yum update -y"
        PKG_INSTALL="yum install -y"
        PKG_UPGRADE="yum upgrade -y"
        ;;
    *)
        echo -e "${RED}Error: Unsupported distribution: $ID${NC}" >&2
        exit 1
        ;;
esac

echo -e "${GREEN}Detected: $PRETTY_NAME using $PKG_MGR${NC}"

# Update system packages
echo -e "${BLUE}[3/8] Updating system packages...${NC}"
$PKG_UPDATE
$PKG_UPGRADE

# Install vim and nano
echo -e "${BLUE}[4/8] Installing vim and nano...${NC}"
$PKG_INSTALL vim nano

# Create backup directory
mkdir -p "$BACKUP_DIR"

# Backup existing configurations
USER_HOME="/home/$TARGET_USER"
if [[ "$TARGET_USER" == "root" ]]; then
    USER_HOME="/root"
fi

for config in .vimrc .nanorc .bashrc; do
    if [[ -f "$USER_HOME/$config" ]]; then
        cp "$USER_HOME/$config" "$BACKUP_DIR/"
    fi
done

# Configure nano
echo -e "${BLUE}[5/8] Configuring nano...${NC}"
cat > "$USER_HOME/.nanorc" << 'EOF'
set tabsize 4
set autoindent
set linenumbers
set mouse
set softwrap
set titlecolor brightwhite,blue
set statuscolor brightwhite,green
set keycolor cyan
set functioncolor green

# Include syntax highlighting
include "/usr/share/nano/*.nanorc"
EOF

# Configure vim
echo -e "${BLUE}[6/8] Configuring vim...${NC}"
cat > "$USER_HOME/.vimrc" << 'EOF'
" Basic settings
set number                " Show line numbers
set relativenumber        " Show relative line numbers
set tabstop=4            " Tab width
set shiftwidth=4         " Indentation width
set expandtab            " Convert tabs to spaces
set autoindent           " Auto-indent new lines
set smartindent          " Smart indentation
set hlsearch             " Highlight search results
set incsearch            " Incremental search
set ignorecase           " Case-insensitive search
set smartcase            " Case-sensitive if uppercase used
set mouse=a              " Enable mouse support
set backspace=indent,eol,start " Better backspace behavior

" Visual settings
syntax on                " Enable syntax highlighting
set background=dark      " Dark background
set cursorline          " Highlight current line
set showmatch           " Show matching brackets

" Performance
set lazyredraw          " Don't redraw during macros
set ttyfast             " Fast terminal connection

" File handling
set encoding=utf-8      " Use UTF-8 encoding
set fileformat=unix     " Use Unix line endings

" Status line
set laststatus=2        " Always show status line
set ruler               " Show cursor position
EOF

# Set proper ownership and permissions
chown "$TARGET_USER:$TARGET_USER" "$USER_HOME/.vimrc" "$USER_HOME/.nanorc"
chmod 644 "$USER_HOME/.vimrc" "$USER_HOME/.nanorc"

# Set default editor using update-alternatives
echo -e "${BLUE}[7/8] Setting default editor...${NC}"
if command -v update-alternatives &> /dev/null; then
    update-alternatives --install /usr/bin/editor editor /usr/bin/vim 10
    update-alternatives --install /usr/bin/editor editor /usr/bin/nano 20
    
    if [[ "$DEFAULT_EDITOR" == "vim" ]]; then
        update-alternatives --set editor /usr/bin/vim
    else
        update-alternatives --set editor /usr/bin/nano
    fi
fi

# Add EDITOR environment variable to .bashrc
if ! grep -q "export EDITOR=" "$USER_HOME/.bashrc" 2>/dev/null; then
    echo "export EDITOR=$DEFAULT_EDITOR" >> "$USER_HOME/.bashrc"
    chown "$TARGET_USER:$TARGET_USER" "$USER_HOME/.bashrc"
    chmod 644 "$USER_HOME/.bashrc"
fi

# Verify installation
echo -e "${BLUE}[8/8] Verifying installation...${NC}"
vim --version | head -1
nano --version | head -1

# Check configuration files
if [[ -f "$USER_HOME/.vimrc" && -f "$USER_HOME/.nanorc" ]]; then
    echo -e "${GREEN}Configuration files created successfully${NC}"
else
    echo -e "${RED}Error: Configuration files not found${NC}" >&2
    exit 1
fi

# Check default editor
if command -v update-alternatives &> /dev/null; then
    CURRENT_EDITOR=$(update-alternatives --query editor | grep "Value:" | cut -d' ' -f2)
    echo -e "${GREEN}Default editor set to: $CURRENT_EDITOR${NC}"
fi

echo -e "${GREEN}✓ Text editor configuration completed successfully!${NC}"
echo -e "${YELLOW}Note: Run 'source ~/.bashrc' or restart your shell to apply environment changes${NC}"
echo -e "${YELLOW}Backup created at: $BACKUP_DIR${NC}"