#!/bin/bash
# Idea and interface taken from https://github.com/macmade/host-manager

path="/etc/hosts"
addusage="Usage: `basename $0` --add host address"
remusage="Usage: `basename $0` --remove host"
listusage="Usage: `basename $0` --list [127.]"
case "$1" in
--add)
  if [ $# -eq 3 ]; then
    if [[ -n $(grep "^$3.*[^A-Za-z0-9\.]$2$" ${path}) ]]; then
      echo "Duplicate address/host combination, ${path} unchanged."
    else
      printf "$3\t$2\n" >> ${path}
    fi
  else
    echo $addusage;
  fi 
  ;;
--remove)
  if [ $# -eq 2 ]; then
    sed -i '' "s/^[^#].*[^A-Za-z0-9\.]$2$//g;/^$/d" ${path}
  else
    echo $remusage;
  fi 
  ;;
--list)
  if [ $# -eq 2 ]; then
    grep "^$2" ${path}
  else 
	cat ${path} | grep -v "^#"
  fi 
  ;;
*)
  echo $addusage;
  echo $remusage;
  echo $listusage;
esac