Generate Ramdon String on Shell

# Bash function to generate the random alphanumeric string with provided length.
randomString() {
    DEFAULT_LENGTH=6

    # if the parameter is not null, apply new length
    if [ ! -z "$1" -a "$1" != " " ]; then
        LENGTH=$1
    else
        LENGTH=$DEFAULT_LENGTH
    fi
    echo $LENGTH;

    LC_ALL=C tr -dc 'a-zA-Z0-9' < /dev/urandom | fold -w $LENGTH | head -n 1
}

Test One:

MyRadomString=$(randomString)
echo "My Radom String: '$MyRadomString'";

# Output:
My Radom String: 'a2d6sd';

Test Two:

MyRadomString=$(randomString 8)
echo "My Radom String2: $MyRadomString";

# Output:
My Radom String2: 'S2sP6sk7';