echo "hello world" > myfile

echo "hello world" >> myfile

#! /bin/bash

#查询函数
search()
{
  clear
  echo -e "Please enter name >>>\c"
  read NAME
  #如果记录为空
  if [ ! -f ./record ];then
    echo "you must have some scores before you can search!"
    sleep 2
    clear
    return 
  fi
  #没有输入名字进行查询
  if [ -z "$NAME" ];then
    echo "you didn't enter a name!"
    echo -e "Please enter name >>>\c"
    read NAME
  fi

  grep -i "$NAME" ./record 2> /dev/null

  case "$?" in
   1) echo "Name not in record."
    ;;
   2) echo "you didnt eter a name to search";
    sleep 2;
    search;;
  esac
}

#增加信息
add()
{
  clear
  echo "Enter name and score of a record"
  echo -e "\c"
  if [ ! -f ./record ];then
    touch record
  fi

  read NEWNAME
  #关于输出重定向，>代表覆盖式的写入 ，>>代表添加式的写入
  echo "$NEWNAME" >>./record

  sort -o ./record ./record
}

#删除学生信息
delete()
{
  clear 
  echo -e "Please enter delete name"
  read NAME

  if [ ! -f ./record ];then
   echo "this name is not in record"
  else
   cp record record.bak
   rm -f record
   grep -v "$NAME" ./record.bak > record
   rm -f record.bak
   fi
}

#显示所有的记录函数
display()
{
  more ./record
}

#利用vim编辑器编辑函数
edit()
{
 vim ./record
}

#屏幕帮助操作
help()
{
 clear
 echo "this is a student record program by unix shell language!"
}

#推出程序
quit()
{
 clear
 exit
}

clear
while true
do
  echo "*********************************************"
  echo "****   student record menu  ****"
  echo "*********************************************"
  echo "---------------------------------------------"
  echo "#############################################"
  echo "    1-search a record    "
  echo "    2-add a record     "
  echo "    3-delete a record    "
  echo "    4-dispaly all records   "
  echo "    5-edit record with vim   "
  echo "    H-help       "
  echo "    Q-exit       "
  echo "#############################################"
  echo -e -n "Please enter your choice [1,2,3,4,5,6,H,Q]:\c"
  read CHOICE

  case $CHOICE in
  1) search;;
  2) add; clear;;
  3) delete; clear;;
  4) display;;
  5) edit; clear;;
  H|h) help;;
  Q|q) quit;;
  *) echo "Invailid choice!";
  sleep 2;
  clear;;
  esac
 done