Linux原理及应用——专题0：Shell实例.ppt

1、LINUX原理及应用,武汉大学计算机学院 李文海 ,shell程序的应用,shell程序的定义 命令文件：包含一串简单命令 shell程序：包含复杂的命令组合 何时使用shell程序设计语言 当问题的解决需要使用多个标准命令时，可以使用shell命令文件； 如果处理的问题比较复杂，可以使用shell程序设计语言,shell应用实例,假设用户要编写一个菜单驱动应用程序以管理UNIX书籍。用户希望能够更新图书列表，了解指定的图书是否在库中，是否借出，谁以及何时借出。 当然，这是一个典型的数据库应用，但是我们的目标是练习使用一些UNIX命令，给用户一些如何把命令组成有用程序的感受。,UNIX图书库程

2、序-ULIB层次图,ULIB,EDIT,edit菜单,REPORT,report菜单,EDIT,增加一条记录,DISPLAY,显示一条记录,UPDATE,更新记录状态,DELETE,删除一条记录,REPORT_NO,生成报表,主菜单,ULIB程序源代码,$ cat -n ULIB 1 # UNIX library 2 # ULIB: This program is the main driver for the UNIX 3 # library application program. It shows a brief 4 # startup message and then displays

3、 the main menu. 5 # It invokes the appropriate program according to the 6 # user selection. 7 BOLD=tput smso #将粗体显示的终端代码保存在BOLD中 8 NORMAL=tput rmso #将正常显示的终端代码保存在NORMAL中 9 export BOLD NORMAL # 使上述变量成为全局变量 10 # show the title and a brief message before showing,ULIB程序源代码,11 # the main menu 12 tput cle

4、ar #清屏 13 tput cup 5 15 #置光标于5行15列 14 echo ”$BOLDSuper Duper UNIX Library” # 以粗体显示 15 tput cup 12 10 #置光标于12行10列 16 echo ”$NORMALThis is the UNIX library application” 17 tput cup 14 10 ; #置光标于14行10列 18 echo ”Please enter any key to continue._bc” 19 read answer # 读用户输入 20 error_flag=0 #将error_flag初始化

5、为0,ULIB程序源代码,21 while true # 一直循环 22 do 23 if $error_flag -eq 0 #检查错误 24 then 25 tput clear # 清屏 26 tput cup 5 10 27 echo ”UNIX Library - $BOLDMAIN MENU$NORMAL” 28 tput cup 7 20;echo ”0:$BOLDEXIT$NORMAL this program” 29 tput cup 9 20 ; echo ”1: $BOLDEDIT$NORMAL Menu” 30 tput cup 11 20 ; echo ”2: $BO

6、LDREPORTS$NORMAL Menu” 31 error_flag=0 # 重置error_flag 32 fi,ULIB程序源代码,33 tput cup 13 10 ; echo ”Enter your choice_bc” 34 read choice #读用户选择 35 # 36 # case construct for checking the user selection 37 # 38 case $choice in #检查输入 39 0 ) tput clear ; exit 0 ; 40 1 ) EDIT ; # 调用EDIT程序 41 2 ) REPORTS ; #

7、调用REPORT程序 42 * ) ERROR 20 10 # 调用ERROR程序 43 tput cup 20 1 ; tput ed #清除从光标处到屏幕底部的部分 44 error_flag=1 ; # 设置错误标志 45 esac 46 done 47 exit 0 # exit the program,ULIB程序初始屏幕,Super Duper UNIX Library This is the UNIX library application Please enter any key to continue._,ULIB程序主菜单屏幕 UNIX Library MAIN MENU,

8、0:EXIT this program 1:EDIT Menu 2:REPORTS Menu Enter your choice_,ULIB程序的错误信息屏幕UNIX Library MAIN MENU,0:EXIT this program 1:EDIT Menu 2:REPORTS Menu Enter your choice_6 Wrong Input. Try again. Press any key to continue._,ERROR程序源代码,$ cat -n ERROR 1 # 2 # ERROR: This program displays an error message

9、 and 3 # waits for user input to continue. It displays the 4 # message at the specified row and column. 5 # 6 tput cup $1 $2 # 置光标位置 7 echo ”Wrong Input. Try again.” # 显示错误信息 8 echo ”Press any key to continue._bc”# 显示提示 9 read answer # 读用户输入 10 exit 0 $_,EDIT程序源代码,$ cat -n EDIT 1# 2# UNIX library 3#

10、 EDIT: This program is the main driver for the EDIT 4# program.It shows the EDIT menu and invokes the 5# appropriate program according to the user selection. 6# 7 error_flag=0 # 初始化error_flag,EDIT程序源代码,8 while true 9 do 10 if $error_flag -eq 0 # 检查错误代码 11 then 12 tput clear ; tput cup 5 10 13 echo ”

11、UNIX Library - $BOLDEDIT MENU$NORMAL” 14 tput cup 7 20 15 echo ”0: $BOLDRETURN$NORMALTo the Main Menu” 16 tput cup 9 20; echo ”1: $BOLDADD$NORMAL” 17 tput cup 11 20; echo ”2: $BOLDUPDATE STATUS$NORMAL” 18 tput cup 13 20; echo ”3: $BOLDDISPLAYNORMAL” 19 tput cup 15 20; echo ”4: $BOLDDELETE$NORMAL” 20

12、 fi 21 error_flag=0 # 重置错误标志 22 tput cup 17 10; echo ”Enter your choice_bc” 23 read choice # 读用户选择,EDIT程序源代码,24 # 25 # case construct for checking the user selection 26 # 27 case $choice in # 检查用户输入 28 0) exit 0; # 返回主菜单 29 1) ADD; # 调用ADD程序 30 2) UPDATE; # 调用UPDATE程序 31 3) DISPLAY; # 调用DISPLAY程序 32

13、 4) DELETE; # 调用DELETE程序 33 *) ERROR 20 10 # 调用ERROR程序 34 tput cup 20 1; tput ed #清除从光标处到屏幕底部的部分 35 error_flag=1; # 设置error_flag 36 esac 37 done 38 exit 0 # exit the program $_,EDIT菜单:ULIX Library EDIT MENU,0: RETURN To the Main Menu l: ADD 2: UPDATE STATUS 3：DISPLAY 4：DELETE Enter your choice_,ADD程

14、序源代码,假设记录所有UNIX图书信息的库文件名为ULIB_FILE；同时还假设在ULIB_FILE中每本书按照下述记录格式保存信息： *Title（书名）：例如UNIX Unbound *Author（作者）：例如Afzal Amir *Category（种类）：例如Textbook 假设有三种有效的类别： *System books（系统书）：简写为sys *Reference books（参考书）：简写为ref *Textbooks（教科书）：简写为tb *Status（状态）：in表明在库中，out表明借走。 *Borrowers name（借阅者姓名）：若状态为in则该字段为空，否则

15、该字段为借阅者姓名。 *Date（日期）：若状态为in则该字段为空，否则该字段为借出的时间。,ADD程序源代码,$ cat -n ADD 1 # UNIX library 2 # ADD: This program adds a record to the library 3 # file(ULIB_FILE).It asks the title,author,and 4 # category of the book. After adding the 5 # information to the ULIB_FILE file,it prompts 6 # the user for the n

16、ext record. 7 answer=y # 初始化answer为yes,ADD程序源代码,8 while ”$answer” = y 9 do 10 tput clear 11 tput cup 5 10 ; echo ”UNIX Library - $BOLDADD MODE” 12 echo ”$NORMAL 13 tput cup 7 23 ; echo ”Title:” 14 tput cup 9 22 ; echo ”Author:” 15 tput cup 11 20 ; echo ”Category:” 16 tput cup 12 20;echo”sys;system,r

17、ef:reference,tb: textbook” 17 tput cup 7 30 ; read title 18 tput cup 9 30 ; read author 19 tput cup 11 30 ; read category 20 status=in # 设置状态为in 21echo ”$title:$author;$category:$status:$bname:$date” ULIB_FILE 22 tput cup 14 10 ; echo ”Any more to add? (Y)es or (N)o_bc”,ADD程序源代码,23 read answer 24 ca

18、se $answer in 25 Yy* ) answer=y ; #以Y或y开头的字表示yes 26 * ) answer=n ; #其他字表示no 27 esac 28 done 29 exit 0 $_,ADD程序产生的屏幕,UNIX Library - ADD MODE Title： Author： Category： sys：system, ref: reference, tb: textbook,信息输入且记录已保存后的屏幕,UNIX Library - ADD MODE Title：UNIX Unbounded Author：Afzal Amir Category：tb sys：

19、system，ref：reference，tb：textbook Any more to add? (Y)es or（N）o_ 若刚才的记录是文件中惟一的记录，ULIB_FILE文件的内容如下： UNIX Unbounded:Afzal Amir:tb:in: 行尾的两个冒号是变量bname和date的占位符。,DISPLAY程序源代码,$ cat -n DISPLAY 1 # UNIX library 2 # DISPLAY: This program displays a specified 3 # record from the ULIB_FILE. It asks the 4 # Au

20、thor/Title of the book, and displays the 5 # specified book is not found in the file. 6 # 7 OLD_IFS=”$IFS” # 保存老分隔符 8 answer=y # 初始化answer为y,DISPLAY程序源代码,9 while ”$answer” = y 10 do 11 tput clear;tput cup 3 5;echo ”Enter the Author/Title_bc” 12 read response 13 grep -i ”$response” ULIB_FILETEMP #查找指

21、定书籍 14 if -s TEMP # 若找到 15 then 16 IFS=”:” # 设置分隔符为冒号 17 read title author category status bname date TEMP 18 tput cup 5 10 19 echo ”UNIX Library - $BOLDDISPLAY MODE$NORMAL” 20 tput cup 7 23 ; echo ”Title: $title” 21 tput cup 8 22 ; echo ”Author: $author”,DISPLAY程序源代码,22 case $category in # check th

22、e category 23 TtBb) word=textbook ; 24 SsYySs) word=system ; 25 RrEeFf) word=reference ; 26 *) word=undefined ; 27 esac 28 tput cup 9 20 ; echo ”Category: $word” 29 tput cup 10 22 ; echo ”Status:$status” 30 if ”$status” = ”out” # 若借出 31 then # 显示其他信息 32 tput cup 11 14 ; echo ”Checked out by: $bname”

23、 33 tput cup 12 24 ; echo ”Date: $date” 34 fi,DISPLAY程序源代码,35 else # 未找到书 36 tput cup 7 10 ; echo ”$response not found” 37 fi 38 tput cup 15 10 ; echo ”Any more to look for? (Y)es or (N)o_bc 39 read answer # 读用户回答 40 case $answer in 41 Yy*) answer=y ; 42 *) answer=n ; 43 esac 44 done 45 IFS=”$OLD_IF

24、S” # 恢复分隔符旧值 46 exit 0 $_,DISPLAY程序提示信息屏幕,Enter the Author/Title_,DISPLAY程序的显示屏幕,UNIX Library DISPLAY MODE Title: UNIX Unbounded Author: Afzal Amir Category：textbook Status: in Any more to look for？ (Y)es or (N)o_,DISPLAY程序的显示错误信息屏幕,Enter the Author/TitleXYZ XYZ not found Any more to look for? (Y)es

25、 or (N)o_,UPDATE程序源代码,$ cat -n UPDATE 1 # UNIX library 2 # UPDATE: This program updates the status of a 3 # specified book. It asks the Author/Title of the 4 # book,and changes the status of the specified 5 # book from in (checked in) to out (checked out), 6 # or from out to in.If the book is not fo

26、und in 7 # the file, an error message is displayed. 8 OLD_IFS=”$IFS” # 保存分隔符 9 answer=y,UPDATE程序源代码,10 while ”$answer” = y 11 do 12 new_status= ; new_bname= ; new_date= # 说明空变量 13 tput clear # 清屏 14 tput cup 3 5 ; echo ”Enter the Author/Title_bc” 15 read response 16 grep -i ”$response” ULIB_FILETTEM

27、P #查找指定书 17 if -s TTEMP # 找到 18 then 19 IFS=”:” #设置IFS为冒号 20 read title author category status bname date TTEMP 21 tput cup 5 10 22 echo ”UNIX Library - $BOLDUPDATE STATUS MODE$NORMAL” 23 tput cup 7 23 ; echo ”Title: $title” 24 tput cup 8 22 ; echo ”Author: $author”,UPDATE程序源代码,25 case $category in

28、26 TtBb) word=textbook ; 27 SsYySs) word=system ; 28 RrEeFf) word=reference ; 29 *) word=undefined ; 30 esac 31 tput cup 9 20 ; echo ”Category: $word”#显示类别 32 tput cup 10 22 ; echo ”Status: $status” 33 if ”$status” = ”in” 34 then 35 new_status=out 36 tput cup 11 18 ; echo ”New status: $new_status” 3

29、7 tput cup 12 14 ; echo ”Checked out by: _bc” 38 read new_bname 39 new_date=date+%D 40 tput cup 13 24 ; echo ”Date: $new_date”,UPDATE程序源代码,41 else 42 new_status=in 43 tput cup 11 14 ; echo ”Checked out by: $bname” 44 tput cup 12 24 ; echo ”Date: $date” 45 tput cup 15 18 ; echo ”New status: $new_stat

30、us” 46 fi 47 grep -iv “$title:$author:$category:$status:$bname: $date” ULIB_FILETEMP #挑出与指定模式不匹配的行 48 cp TEMP ULIB_FILE 49 echo “$title:$author:$category:$new_status: $new_bname: $new_dateULIB_FILE 50 else 51 tput cup 7 10 ; echo ”$response not found” 52 fi,UPDATE程序源代码,53 tput cup 16 10 ; echo ”Any

31、more to update? (Y)es or (N)o_bc 54 read answer #读用户输入 55 case $answer in 56 Yy*) answer=y ; 57 *) answer=n ; 58 esac 59 done 60 IFS=”$OLD_IFS” #恢复分隔符旧值 61 rm TEMP TTEMP 62 exit 0 $_,UPDATE程序显示屏幕,UNIX Library - UPDATE STATDS MODE Title: UNIX Unbounded Author: Afzal Amir Category: textbook Status: in

32、 New status: out Checked out by: Steve Fraser Date: 12/12/05 Any more to update?(Y)es or (N)o_,DELETE程序源代码,$ cat -n DELETE 1 # UNIX library 2 # DELETE: This program deletes a specified record 3 # from the ULIB_FILE. It asks the Author/Title of 4 # the book, and displays the specified book, and 5 # d

33、eletes it after confirmation, or shows an error 6 # message if the book is not found in the file. 7 # 8 OLD_IFS=”$IFS” # save the IFS setting 9 answer=y,DELETE程序源代码,10 while ”$answer” = y 11 do 12 tput clear ; tput cup 3 5 ; echo ”Enter the Author/Title_bc” 13 read response 14 grep -i ”$response” UL

34、IB_FILETEMP #查找指定书籍 15 if -s TEMP #找到 16 then 17 IFS=”:” 18 read title author category status bname date TEMP 19 tput cup 5 10 20 echo ”UNIX Library - $BOLDDELETE MODE$NORMAL” 21 tput cup 7 23 ; echo ”Title: $title” 22 tput cup 8 22 ; echo ”Author: $author”,DELETE程序源代码,23 case $category in 24 TtBb)

35、word=textbook ; 25 SsYySs) word=system ; 26 RrEeFf) word=reference ; 27 *) word=undefined ; 28 esac 29 tput cup 9 20 ; echo ”Category: $word” 30 tput cup 10 22 ; echo ”Status: $status” 31 if ”$status” = ”out” 32 then 33 tput cup 11 14 ; echo ”Checked out by: $bname” 34 tput cup 12 24 ; echo ”Date: $

36、date” 35 fi,DELETE程序源代码,36 tput cup 13 20 ; echo ”Delete this book?(Y)es or (N)o _bc” 37 read answer 38 if $answer = y -o $answer = Y 39 then 40 grep -iv “$title:$author:$category:$status: $bname:$date” ULIB_FILETEMP #挑出与指定模式不匹配的行 41 mv TEMP ULIB_FILE 42 fi 43 else # if book not found 44 tput cup 7

37、10 ; echo ”response not found” 45 fi,DELETE程序源代码,46 tput cup 15 10 ; echo ”Any more to delete? (Y)es or (N)o _bc 47 read answer 48 case $answer in 49 Yy*) answer=y ; 50 *) answer=n ; 51 esac 52 done 53 IFS=”$OLD_IFS” 54 rm TEMP 55 exit 0 $_,DELETE程序的显示,UNIX Library DELETE MODE Title: UNIX Unbounded

38、Author: Afzal Amir Category: textbook Status: out Checked out by: Steve Fraser Date: 12/12/05 Delete this book? (Y)es or (N)oY Any more to delete? (Y)es or (N)o_,REPORTS程序源代码,$ cat -n REPORTS 1 # UNIX library 2 # REPORTS: This program is the main driver for 3 # the REPORTS menu. It shows the reports

39、 menu and 4 # invokes the appropriate program according to 5 # the user selection. 6 # 7 error_flag=0 #初始化错误标志,REPORTS程序源代码,8 while true 9 do 10 if $error_flag -eq 0 11 then 12 tput clear ; tput cup 5 10 13 echo ”UNIX Library - $BOLDREPORTS MENU $NORMAL” 14 tput cup 7 20 15 echo ”0: $BOLDRETURN$NORM

40、ALTo the Main Menu” 16 tput cup 9 20 ; echo ”1: Sorted by $BOLDTITLES $NORMAL” 17 tput cup 11 20 ; echo ”2: Sorted by $BOLDAUTHOR $NORMAL” 18 tput cup 13 20 ; echo ”3: Sorted by $BOLDCATEGORY $NORMAL” 19 fi 20 error_flag=0 21 tput cup 17 10 ; echo ”Enter your choice _bc”,REPORTS程序源代码,22 read choice

41、23 # 24 # case construct for checking the user selection 25 # 26 case $choice in 27 0) exit 0; # 返回 main menu 28 1) REPORT_NO 1; #调用REPORT_NO程序,参数为1 29 2) REPORT_NO 2; #调用REPORT_NO程序,参数为2 30 3) REPORT_NO 3; #调用REPORT_NO程序,参数为3 31 *) ERROR 20 10 #调用error程序 32 tput cup 20 1 ; tput ed #从光标处清除屏幕 33 error_flag=1; #设置错误标志 34 esac 35 done 36 exit 0 $_,REPORTS菜单,UNIX Library REPORTS MENU 0: