#!/bin/sh

# Checks for valid number of command arguments
if [ $# -eq 0 -o  $# -gt 2 ]; then
        echo "Invalid number of arguments:  1 or 2 only!"
        exit 1
fi

case $# in

"1")  # Checks for validity of command argument 1
        echo $1 | egrep -si "^[a-z]+$"

        # Error message for invalid argument 1
        if [ $? -ne 0 ]; then
                echo "Invalid argument 1:  Letters only!"
                exit 2
        fi

        # Searches through all files in the current working                      
        # directory
        for i in `find . -type f -print`
        do
                # If current file is readable then search for the   
                # string
                if [ -r $i ]; then
                        grep -li "$1 " $i
                fi
        done

"2")  # Checks for validity of command argument 1
        echo $1 | egrep -si "^[a-z]+$"

        # Error message for invalid argument 1
        if [ $? -ne 0 ]; then
                echo "Invalid argument 1:  Letters only!"
                exit 2
        fi

        # Checks for validity of command argument 2
        find $2 -type d

        # Error message for invalid argument 2
        if [ $? -ne 0 ]; then
                echo "Invalid argument 2:  Directory path only!"
                exit 3
        fi

        # Searches through all files in the directory specified
        for i in `find .$2  -type f -print`
        do
                # If current file is readable then search for the         
                # string
                if [ -r $i ]; then
                        grep -li "$1 " $i
                fi
        done;;
esac

exit 0