hostfile

#!/bin/bash

#####################################################################
## Simple script for listing, adding and removing hostfile entries ##
##                                                                 ##
## Kevin Bentlage <kevin@bentlage.nu>                              ##
#####################################################################

# Host File
hostFile="/etc/hosts"

# Usage
# Printing usage information
function usage {
    echo -e "\nUsage"
    echo -e "Add entry      \t hostfile -a <hostname> <ip>";
    echo -e "Remove entry   \t hostfile -r <hostname>";
    echo -e "List           \t hostfile -l";
    echo -e "Edit hostfile  \t hostfile -e";
}

# Show Help
# Show help and usage information
function showHelp {
    usage
    exit
}

# List Entries
# List all entries in hostfile
function listEntries {
    cat "$hostFile"
}

# Add Entry
# Add new entry to hostfile when it not present yet
function addEntry {

    # Prepare line
    hostLine="$ip\t$hostname\t# Added on $(date +'%m-%d-%Y')"
    
    if [ -n "$(grep $hostname $hostFile)" ]
    then
        echo -e "$hostname already exists:\n\n$(grep $hostname $hostFile)"
    else
        echo "Adding $hostname to $hostFile";
        sudo sh -c -e "echo '$hostLine' >> $hostFile";
        if [ -n "$(grep $hostname $hostFile)" ]
        then
            echo -e "$hostname was succesfully added\n\n$(grep $hostname $hostFile)";
        else
            echo "Failed to add $hostname, Try again!";
        fi
    fi
}

# Remove Entry
# Removes entry from hostfile if exists
function removeEntry {
    echo "Removing hostfile entry";
    
    if [ -n "$(grep $hostname $hostFile)" ]
    then
        echo "$hostname found in $hostFile, Removing now...";
        sudo sed -i ".bak" "/$hostname/d" $hostFile
    else
        echo "$hostname was not found in $hostFile";
    fi
}

# Edit Entries
# Edit entries in hostfile
function editEntries {
    sudo vi "$hostFile"
}

# Catch attributes
while getopts "a:r:le" opt;
  do
    case $opt in
      l)
        action="L"
      ;;
      a)
        action="A"
        hostname=$OPTARG
        eval "ip=\${$OPTIND}"
        shift 2
      ;;
      r)
        action="R"
        hostname=$OPTARG
      ;;
      e)
        action="E"
      ;;
      \?)
        echo -e "Invalid option: -$OPTARG"
        showHelp
      ;;
    esac
done

# When no action is given, show help
if [ -z $action ]; then
  showHelp
fi

# List action
if [ $action == "L" ]; then
  listEntries
  exit
fi

# Add action
if [ $action == "A" ]; then
  if [ -z $hostname ]; then
    echo -e "Missing argument: <hostname>"
    showHelp
  fi
  if [ -z $ip ]; then
    echo -e "Missing argument: <ip>"
    showHelp 
  fi
  addEntry
  exit
fi

# Remove action
if [ $action == "R" ]; then
  if [ -z $hostname ]; then
    echo -e "Missing argument: <hostname>"
    showHelp
  fi
  removeEntry
  exit
fi

# Edit action
if [ $action == "E" ]; then
  editEntries
  exit
fi