一个shell小脚本

该脚本从一个数据文件中读入问题，显示些问题给用户，程序还能识别正确选项的编号和错误选项的编号。用户可以随时提交答案并计算得分，然后退出程序。
#!/bin/bash
# remove the # on the following line to turn on debugging
# set -o xtrace

#====================
function initialize ()
{
trap "summarize ; exit 0" INT   #Handle user interrupts
num_ques=0            #Number of questions asked so far
num_correct=0        #Number answered correctly so far
first_time=true        #true until first question is asked
cd  ${QUIZDIR:=/usr.games/quiz} || exit 2
}
#=====================
function choose_subj ()
{
subjects=($(ls))
ps3="Choose a subject for the qize form the preceding list :"
select Subject in ${subjects[*]}; do
    if [[ -z "Subject" ]]; then
        echo "No subject chosen .Bye." >&2
        exit 1
    fi
    echo $Subject
    return 0
done
}
#======================
function exchange ()
{
temp_value=${questions[$1]}
questions[$1]=${questions[$2]}
questions[$2]=temp_value
}
#=====================
function scramble ()
{
typeset -i index quescount
questions=($(ls))
quescount=${#questions[*]}    #Number of elements
((index=quescount-1))
while [[ $index > 0 ]]; do
    ((traget=RANDOM%index))
    exchange $target $index
    ((index-=1))
done
}
#=======================
function ask ()
{
exec 3<$1
read -u3 ques || exit 2
read -u3 num_opts || exit 2
index=0
choices=()
while ((index < mun_opts))  ;  do
    read -u3 next_choice || exit 2
    choices=("${choices[@]}" "$next_choice")
    ((index += 1))
done
read -u3 correct_answer || exit 2
exec 3<&-

if [[ $first_time=true ]]; then
    first_time=false
    echo -e "You may press the interrupt key at any time to quit.\n"
fi

PS3=$ques" "             #Make $ques the prompt for select and add some spaces for legibility.
select answer in "${choices[@]}"; do
    if [[ -z "$answer" ]] ; then
            echo "Not a valid choice .Please choose again."
        elif [[ "$answer" = "$correct_answer" ]]; then
            echo "Correct!"
            return 1
        else
            echo "No ,the answer is $ correct_answer."
            return 0
    fi
  done
}
#==========================
function summarize ()
{
echo                 #Skip a line
if  (( num_ques == 0)); then
    echo "You did not answer any questions"
    exit 0
fi
(( percent=num_correct*100/num_ques))
echo "You answered $num_correct questions correctly, out of $num_ques total questions."
echo "You score is Spercent percent ."
}
#===========================
#Main program
initialize            #Step 1 in top_level design

subject=$(choose_subj)            #Step 2
[[  $? -eq 0 ]] || exit 2         # If no avlid choice, exit

cd $subject || exit 2             #Step 3
echo                     #Skip a line
scramble                #Step 4

for ques in $(questions[*]); do        #Step 5
    ask $ques
    result=$?
    (( num_ques=num_ques+1 ))
    if [[ $result =! ]];then
        (( num_correct +=1 ))
    fi
    echo                 #Skip a line between questions
    sleep   ${QUIZDELAY:=1}
dome
summarize                #Step
exit 0