Linux笔记 #08# shell编程从零开始到低配学生管理系统

#!/bin/bash

# 实现两个函数
# 1 appendToFile()追加一行到文件
# 2 readFile()把文件中所有内容逐行写到控制台

echo "welcome to bash!"
echo ‘welcome to bash!‘
printf ‘%-5s %-10s %-4s\n‘ No Name Mark
printf ‘%-5s %-10s %-4.2f\n‘ 1 Jack 20.012
# welcome to bash!
# welcome to bash!
# No    Name       Mark
# 1     Jack       20.01

v=‘sads‘
# v2 = ‘dasdas‘ 
# =>  v2: command not found（这是是一个错误示范）
echo v2 # => v2
echo $v # => sads
echo ${v} # => sads
echo ‘hello, $v and ${v}‘ # => hello, $v and ${v}
echo "hello, $v and ${v}" # => hello, sads and sads

echo ${#v} # => 4（字符串长度）

let digit1=3 
let digit2=2
let result=digit1+digit2
echo $result # => 5

# echo "4 * 0.5" | bc

echo "重定向到文本" > text.txt
echo "追加到目标文件" >> text.txt
# $ cat text.txt
# 重定向到文本
# 追加到目标文件

array[0]=‘daasd‘
array[3]=‘asassd‘
echo ${array[0]} # => daasd
echo ${array[*]} # => daasd asassd
echo ${!array[*]} # => 0 3

# $ sh -v linux.sh
# $ sh -x linux.sh 进行调试打印
function f() {
    echo ‘接下来是f的输出：‘
    echo $1
    echo $2
    echo $@
    echo $*
}
f 1 ‘hello‘ 3 # 调用函数
# 接下来是f的输出：
# 1
# hello
# 1 hello 3
# 1 hello 3
FILENAME=student
appendToFile() {
    # arg1: filename, arg2: content
    echo $1 >> $FILENAME
}
appendToFile "小张 25 未婚"

readFile() {
    while read LINE
    do
        echo $LINE
    done < $FILENAME
}
echo ‘invoke readFile:‘
readFile
# invoke readFile:
# 小张 25 未婚
# 小张 25 未婚

#!/bin/bash

# 构造三个类似数据库的文本文件:
# 第一个为学院信息文件，包含字段：
# 学院编号（唯一），学院名称
# 第二个为学生信息文件，包含字段：
# 学号（唯一），学生姓名，所在学院编号，说明（休学suspended，退学dropout）
# 第三个为学生成绩文件，包含字段：
# 学号（唯一），学生姓名，科目名称，成绩；说明（期考final,补考makeup）
# 说明：每个记录占一行；分隔符可以自己选定，建议用”,”； 编码规则自己定；文件名自己定
# 程序功能：要求实现4个功能，每个功能作为一个函数
# 1.向文件中插入记录
# 2.显示文件中的每条记录的每个字段值
# 3.从文件中修改指定学号的记录
# 4.对学生成绩进行统计（包括每个学生总成绩；每个学科前3名和总成绩前5名统计）


newFile() {
    # arg1: filename, arg2: content
    # 例子：appendToFile temp4 "小张 25 未婚"
    echo $2 > $1
}

readFile() {
    # arg1: data_filename
    while read LINE
    do
        echo $LINE
    done < $1
}

saveRecord() {
    # arg1: filename, arg2: content
    # 例子：appendToFile temp4 "小张 25 未婚"
    echo $2 >> $1
}

initTables() { 
    # 数据库文件初始化
    newFile academy "academy_id,academy_name"
    newFile student "stu_id,stu_name,academy_id,stu_description"
    newFile subject "stu_id,stu_name,subject_name,score,subject_description"
}

updateStudentById() {
    # arg1: 学号, arg2：新的记录
    # 例子：updateStudentById ‘2132022129‘ ‘2132022129,李四,001,dropout‘
    oldStr=`grep $1 student` # 把grep的执行结果赋给oldStr
    newStr=$2
    sed -i "s/${oldStr}/${newStr}/" student
}

topStudent() {
    echo ‘topStudent‘
}

echoTitle() {
    echo ‘-------------------------------------------------------‘
    echo $1
    echo ‘-------------------------------------------------------‘
}

endl() {
    echo -e ‘\n‘
}

listRecords() {
    # arg1: data_filename
    i=0
    while read LINE
    do
        let i=i+1
        if [[ i -gt 1 ]]; then
            echo $LINE
        fi
    done < $1
}

initRecords() {
    # 学院信息
    saveRecord academy "001,挪威阿克苏而达学院"
    saveRecord academy "002,哈尔滨佛学院（简称哈佛）"
    # 学生信息
    saveRecord student "2132022129,张三,001,dropout"
    saveRecord student "2132022139,李四,002,dropout"
    saveRecord student "2132022149,王五,001,dropout"
    saveRecord student "2132022159,老王,002,dropout"
    saveRecord student "2132022119,张飞,001,suspended"
    saveRecord student "2132022109,刘备,001,suspended"
    saveRecord student "2132022179,关羽,002,suspended"
    # linux成绩
    saveRecord subject "2132022129,张三,linux,0,makeup"
    saveRecord subject "2132022139,李四,linux,13.5,makeup"
    saveRecord subject "2132022149,王五,linux,23.5,makeup"
    saveRecord subject "2132022119,张飞,linux,99.5,makeup"
    saveRecord subject "2132022109,刘备,linux,0,makeup"
    saveRecord subject "2132022179,关羽,linux,100,final"
    saveRecord subject "2132022159,老王,linux,43.5,makeup"
    # math成绩
    saveRecord subject "2132022129,张三,math,10,final"
    saveRecord subject "2132022139,李四,math,23.5,final"
    saveRecord subject "2132022149,王五,math,33.5,final"
    saveRecord subject "2132022119,张飞,math,89.5,final"
    saveRecord subject "2132022109,刘备,math,0,final"
    saveRecord subject "2132022179,关羽,math,100,final"
    saveRecord subject "2132022159,老王,math,93.5,final"    
}

main() {
    initTables
    initRecords
    
    echoTitle ‘1、学院表一览‘
    listRecords academy; endl
    echoTitle ‘2、学生表一览‘
    listRecords student; endl
    echoTitle ‘3、成绩表一览‘
    listRecords subject; endl
    
    updateStudentById ‘2132022129‘ ‘2132022129,赵云,001,dropout‘
    echoTitle ‘**学生表一览（更新2132022129后）‘
    listRecords student; endl
    topStudent
}

main