fstring

#!/bin/sh

# Function to display usage
usage() {
    echo "Usage: $0 <string> [-e extension]"
    echo "Examples:"
    echo "  $0 \"SEARCH_STRING\"          # Search all files"
    echo "  $0 \"SEARCH_STRING\" -e txt  # Search only .txt files"
    exit 1
}

# Check if at least one argument (search string) is provided
if [ $# -lt 1 ]; then
    usage
fi

SEARCH_STRING="$1"
EXTENSION=""
shift  # Move past the search string

# Parse optional -e flag
while getopts "e:" opt; do
    case $opt in
        e) EXTENSION="$OPTARG";;
        ?) usage;;
    esac
done

# Set the search directory (default is current directory)
SEARCH_DIR="."

# Determine number of CPU cores and xargs command
if [ "$(uname)" = "Darwin" ]; then
    # macOS
    NPROC=$(sysctl -n hw.ncpu)
    # Check for gxargs in common Homebrew locations
    if [ -x "/opt/homebrew/bin/gxargs" ]; then
        XARGS_CMD="/opt/homebrew/bin/gxargs -0 -P $NPROC"
    elif [ -x "/usr/local/bin/gxargs" ]; then
        XARGS_CMD="/usr/local/bin/gxargs -0 -P $NPROC"
    else
        XARGS_CMD="/usr/bin/xargs -0"
        echo "Tip: Install 'findutils' (brew install findutils) for faster parallel execution on macOS" >&2
    fi
elif command -v nproc >/dev/null 2>&1; then
    # Linux
    NPROC=$(nproc)
    XARGS_CMD="xargs -0 -P $NPROC"
elif command -v sysctl >/dev/null 2>&1; then
    # Other BSD
    NPROC=$(sysctl -n hw.ncpu)
    XARGS_CMD="xargs -0"
else
    # Fallback
    NPROC=1
    XARGS_CMD="xargs -0"
fi

# Run find and grep based on whether an extension is provided
if [ -z "$EXTENSION" ]; then
    # No extension: search all files
    find "$SEARCH_DIR" -type f -print0 | $XARGS_CMD grep -l "$SEARCH_STRING" 2>/dev/null
else
    # Extension provided: search only files with that extension
    find "$SEARCH_DIR" -type f -name "*.$EXTENSION" -print0 | $XARGS_CMD grep -l "$SEARCH_STRING" 2>/dev/null
fi