#!/bin/bash
abspath=$(readlink -f "$0") # Set variable abspath to the absolute path where this script is located
dir=$(dirname "$0") # Set variable dir to source directory (the directory used when executing this script, for example "." if the script was executed with ./)
name=$(basename "$0") # Set variable name to name of this script

while getopts "hd:" flag; do
 case $flag in
   h) # Handle the -h flag
   echo "Usage: nc -lk 1900 -e \"$dir/$name -d <path>\"

note: netcat (nc) is not necessary, however this script ($abspath) does not have any networking, meaning you will need netcat or something similar to make the server accessible over a computer network

options:
-h        Display this help screen
-d <path> specify root directory for server (where index and any other files should be located)"
   exit # Display script help information
   ;;
   d) # Handle the -d flag with an argument
   rootdir=$OPTARG
   # Sets the specified path as root directory for server (where index and any other files will be located)
   ;;
   \?) # Handle invalid options
   echo "Internal server error: invalid option. See $dir/$name -h for help." # Display error
   exit
   ;;
 esac
done

if [[ -z $rootdir ]] # Check if variable rootdir has a length of zero
 then
  echo "Internal server error: no root directory specified. See $dir/$name -h for help." # Display error
  exit
 else
  :
fi

if [[ $rootdir == */ ]] # Check if variable rootdir ends in /
 then
  rootdir=${rootdir::-1} # Remove last character from variable rootdir
 else
  :
fi

read input # Set variable input to requested path

if [[ $input == /* ]] # Check if variable input begins with a /
 then
  :
 else
  input=/$input # Add / to beginning of variable input
fi

if [[ $input == */ ]] # Check if requested path is a directory
 then
  path=$rootdir$input/index # Set variable path to index file contained by requested directory
 else
  path=$rootdir$input # Set variable path to requested file
fi

if [[ -a $path ]] # Check if requested file exists
 then
  cat $path # Serve requested file
 else
  echo document not found # Display error
fi

exit