luser-demo03.sh

#!/bin/bash

# Display the UID and username of the user executing this script.
# Display if the user is the gr3yhatt3r user or not.

# Display the UID
echo "Your UID is $(id -u)."

# Only display if the UID does NOT match 1000.
UID_TO_TEST_FOR='1000'
if [[ "${UID}" -ne "${UID_TO_TEST_FOR}" ]]
then
    echo "Your UID does not match ${UID_TO_TEST_FOR}"
    exit 1
fi


# Dsipaly the username.
USER_NAME=$(id -un)

# Test if the command succeeded.
if [[ "${?}" -ne 0 ]]
then
    echo 'The id command did not execute successfully.'
    exit 1
fi
echo "Your username is ${USER_NAME}"

# You can use a string test conditional.
USER_NAME_TO_TEST_FOR='gr3yhatt3r'
if [[ "${USER_NAME}" = "${USER_NAME_TO_TEST_FOR}" ]]
then
    echo "Your username matches ${USER_NAME_TO_TEST_FOR}."
fi

# Test for the != (not equal) for the string.
if [[ "${USER_NAME}" != "${USER_NAME_TO_TEST_FOR}" ]]
then
    echo "Your username does not match ${USER_NAME_TO_TEST_FOR}"
    exit 1
fi

exit 0