Bash script to check if a certain domain is user O365

checkms.sh

#!/bin/bash
# Usage checkms.sh
# domains.txt: file with domains on each line to check
# Output: domains that use O365
# -----
# Usage2 checkms.sh domain.com
# Output: domain if uses 0365, nothing if not
if [ "$#" -eq 1 ]; then
        x=$(curl -s -k "https://login.microsoftonline.com/getuserrealm.srf?login=username@$1&xml=1" | egrep "Federated|Managed")                                                                                  
        if [[ ! -z $x ]]; then
                echo "$1"
        fi
        exit
fi

for i in `cat domains.txt`; do
        x=$(curl -s -k "https://login.microsoftonline.com/getuserrealm.srf?login=username@$i&xml=1" | egrep "Federated|Managed")                                                                                  
        if [[ ! -z $x ]]; then
                echo "$i"
        fi
done