Determine if the given host is localhost

islocalhost

#!/bin/bash
set -e

function isLocalhost {
    local TEST_IP=$(getent hosts $1 | cut -f1 -d\ | head -1)
    local ALL_MY_IPS=$(ip addr | grep inet | grep -v link | cut -f2- -de | cut -f2 -d\  | cut -f1 -d/)
    ( echo $ALL_MY_IPS | grep -q $TEST_IP ) && return 0
    return 1
}

if ( isLocalhost $1 ) ; then
   echo yes
else
   echo no
fi