典型bash脚本

set -o nounset                              # Treat unset variables as an error
read -p "Enter The Users Password: " PASSWD

for UNAME in `cat users.txt`; do
    id $UNAME &> /dev/null

    if [ $? -eq 0 ] ; then
        echo -e "Already exists"
    else
        useradd $UNAME &> /dev/null
        echo "$PASSWD" | passwd --stdin $UNAME &> /dev/null

        if [ $? -eq 0 ] ; then
            echo -e "$UNAME, Create success"
        else
            echo "$UNAME, Create failure"
        fi
    fi
done