A smart Library
#
# This is a smart library designed in shell under linux enverionment
# LINUX Library: This program is the main driver for the LINUXlibrary
# application program . It shows a brief startup messagr
# and then dispalys the main menu.It invokes the appropriate
# program according to the user selection.
#
PATH=$PATH:.
BOLD=`tput smso` # store code for bold mode in BOLD
NORMAL=`tput rmso` # store code for end of the
# bold mode in NORMAL
export BOLD NORMAL # make them recongized by subshells
# -------------------------------add_record------------------------------
#
# LINUX Library
# add_record: This program adds a record to the library file (L_LIB).
# It asks the title , author, and category of the book. After
# adding the information to the -ULIB_FILE file, it prompts
# the user for the next record.
#
add_record(){
answer=y
while [ "$answer" = y ]
do
tput clear
tput cup 05 10
echo -e " LINUX Library . ${BOLD} ADDMODE"
echo -e " ${NORMAL}"
tput cup 07 23
echo " Title: "
tput cup 09 22
echo " Author: "
tput cup 11 20
echo " Catagory: "
tput cup 13 20
echo "sys: system, ref: referance, tb: textbook"
tput cup 14 10
echo -e " Any more to add ? (Y)es or (N)o > _\b\c"
read answer
case $answer in
[Yy]*)
answer=y
;;
[Nn]*)
answer=n
;;
esac
done
continue
}
# -------------------------------update_record---------------------
#
# LINUX Library
# update_record: This program update the status of a specified book. It
# asks the Author/Title of the book, and changes the status
# of the specified book from in (check in) to out (check out),
# or from out to in. If the book is notfound in the file, and
# an error message is displayed.
#
update_record(){
OLD_IFS="$IFS"
answer=y
while [ "$answer" = y ]
do
new_status=
new_bname=
new_date=
# declare empty varible
tput clear
tput clear
tput cup 03 05
echo -e " Enter the Author/Title > -\b\c"
read response
grep -i "$response" LLIB_FILE < TEMP
if [ -s TEMP ]
then
IFS=""
read title author category status bname date < TTEMP
tput cup 05 10
echo -e " LNIUX Library . ${BOLD} UPDATESTATUSMODE ${NORMAL}"
tput cup 07 23
echo " Title : $title"
tput cup 08 22
echo " Author: $author"
case $category in
[Tt][Bb])
word=textbook
;;
[Ss][Yy][Ss])
word=system
;;
[Rr][Ee][Ff])
word=referance
;;
*)
word=undefined
;;
esac
tput cup 09 20
echo " Category: $word" # display the category
tput cup 10 22
echo " Ststus: $status" # display the status
if [ "$status" = "in" ] # if it check in
then
new_status=out # indicate the status
tput cup 11 18
echo " New status: $status"
tput cup 12 14
echo -e " Check out by: _ \b\c"
read new_bname
new_date=`date+%D`
tput cup 13 24
echo " Date: $new_date"
else
new_status=in
tput cup 11 14
echo " Check out by: $bname"
tput cup 12 24
echo " Date: $date"
tput cup 15 18
echo " New status: $new_status"
fi
grep -iv "$status: $author: $category: $status: $bname: $date" LLIB_FILE
>TEMP
cp TEMP LLIB_FILE
echo "$title : $author: $category: $dtatus: $bname: $date" >> LLIB_FILE
else
tput cup 7 10
echo " $response not found"
fi
tput cup 16 10
echo -e " Any more to update ? (Y)es or (N)o > _\b\c"
read answer
case $answer in
[Yy]*)
answer=y
;;
*)
answer=n
;;
esac
done
IFS="$OLD_IFS"
rm TEMP TTEMP
continue
}
# -----------------------------display_recorde----------------------
#
# LINUX Library
# display_recorde: This program display a specified record from the
# LLIB_FILE.It asks the Author/Title of the book, and
# display the specifiedbook is not found in the file.
#
display_record(){
OLD_IFS="$IFS" # save the IFSsetting
answer=y # initialize the answer to indicate yes
while [ "$answer" = y ] # as long as the answer is yes
do
tput clear
tput cup 03 05
echo -e " Enter the Author/Title> _\b\c"
read response
grep -i "$response" LLIB_FILE > TEMP # find the specified book in the file
if [ -s TEMP ] # if it is found
then
IFS=":" # set the IFS to colon
read title author category status bname date < TEMP
tput cup 05 10
echo -e "LINUX Library . ${BOLD} DISPLAYMODE ${NORMAL}"
tput cup 07 23
echo " Title: $title"
tput cup 08 22
echo " Author: $author"
case $category in
[Tt][Bb])
word=textbook
;;
[Ss][Yy][Ss])
word=system
;;
[Rr][Ee][Ff])
word=referance
;;
*)
word=undefined
;;
esac
tput cup 09 20
echo -e " Category: $word" # display the category
tput cup 10 22
echo -e " Status: $status"
if [ "$status" = "out" ]
then
tput cup 11 14
echo " Check out by: $bname"
tput cup 12 24
echo " Date: $date"
fi
else
tput cup 07 10
echo " $response not found "
fi
tput cup 15 10
echo -e "Any more to look for ? (Y)es or (N)o > _\b\c"
read answer
case $answer in
[Yy]*)
answer=y
;;
*)
answer=n
;;
esac
done # end of the while loop
IFS="$OLD_IFS" # restor the IFSto its orgiginal value
continue
}
# ----------------------------delete_record--------------------------
#
# LINUX Library
# delete_record: This program deletes a specified record from the
# LLIB_FILE. It asks the Author/Title of the book,
# and displays the specifiedbook, and deletes it after
# confirmation, or shows an error message.
#
delete_record(){
OLD_IFS="$IFS" # save the IFSsetting
answer=y
# initialize the answer to indicate yes
while [ "$answer" = y ] # as long as the answer is yes
do
sleep 1
tput clear
tput cup 03 05
echo -e " Enter the Author/Title> _\b\c"
read response
grep -i "$response" LLIB_FILE > TEMP # find the specified book in the file
if [ -s TEMP ] # if it is found
then
IFS=":" # set the IFS to colon
read title author category status bname date < TEMP
tput cup 05 10
echo -e "LINUX Library . ${BOLD} DELETEMODE ${NORMAL}"
tput cup 07 23
echo " Title: $title"
tput cup 08 22
echo " Author: $author"
case $category in
[Tt][Bb])
word=textbook
;;
[Ss][Yy][Ss])
word=system
;;
[Rr][Ee][Ff])
word=referance
;;
*)
word=undefined
;;
esac
tput cup 09 20
echo -e " Category: $word" # display the category
tput cup 10 22
echo -e " Status: $status"
if [ "$status" = "out" ]
then
tput cup 11 14
echo " Check out by: $bname"
tput cup 12 24
echo " Date: $date"
fi
tput cup 13 20
echo -e " Delete thsi book ? (Y)es or (N)o > _\b\c"
read answer
if [ $answer y ] || [ $answer = Y ] # test for Y or y
then
grep -iv "$title: $author: $category: $bname: $date" LLIB_FILE
> TEMP
mv TEMP LLIB_FILE
fi
else
tput cup 14 10
echo " $response not found"
fi
tput cup 15 10
echo -e " Any more to delete ? (Y)es or (N)o > _\b\c"
case $answer in
[Yy]*)
answer=y
;;
*)
answer=n
;;
esac
done # end of the while loop
IFS="$OLD_IFS" # restor the IFSto its orgiginal value
continue
}
# -----------------------------show_error--------------------------
# LINUX Library
# show_error: This program display an error message and waits for
# userinput to continue. It dispalys the message at the
# specifiled row and column.
#
show_error(){
tput cup $1 $2 # place the cursor on the screen
echo -e " \07Wrong Input. Try again." # show the error message
row=`expr $1 + 2`
tput cup $row $2
echo -e " Press any key to continue...> _ \b\c" # display the prompt
read answer
continue
}
# -------------------------report_recorde_no-----------------------
#
# LINUX Library
# report_record_no: This program produces reports from the LLIB_FILE
# file It checks for the report number passed to it
# on the command line, sorts and produces reports
# accordingly.
#
report_record_no(){
IFS=":"
case $1 in
1)
sort -f -d -t : LLIB_FILE > TEMP
;;
2)
sort -f -d -t : +1 LLIB_FILE > TEMP
;;
3)
sort -f -d -t : +2 LLIB_FILE > TEMP
;;
esac
#
# read records from the sorted file TEMP. Format and store
# them in PTEMP
#
while read title author category status bname date
do
echo -e "\t Title: $title" >> PTEMP
echo -e "\t Author: $author" >> PTEMP
case $category in
[Tt][Bb] )
word=textbook
;;
[Ss][Yy][Ss] )
word=system
;;
[Rr][Ee][Ff] )
word=referande
;;
*)
word=undefined
;;
esac
echo -e "\t Category: $word" >> PTEMP # format author
echo -e "\t Status: $status " >> PTEMP
if [ "$status" = "out" ]
then
echo -e "\t Check out by: $bname" >> PTEMP
echo -e "\t Date: $date \n" >> PTEMP
fi
echo >> PTEMP
done
tput clear
more -14 PTEMP
rm TEMP PTEMP
continue
}
# ----------------------------edit_record-------------------------
#
# LINUX Library
# edit_record: This program is the main driver for the EDIT program.
# It shows the EDIT menu and invokes the appropriate
# program according to the user selection.
#
edit_record(){
error_flag=0 # inilitalize the error flag, indicating no error.
while true
do
if [ $error_flag -eq 0 ] # check for the error
then
tput clear
tput cup 05 07
echo -e " LINUX Library . ${BOLD} EDIT MENU ${NORMAL}"
tput cup 07 20
echo -e " 0 : ${BOLD} RETURN ${NORMAL}to the Main Menu"
tput cup 09 20
echo -e " 1: ${BOLD} ADD ${NORMAL}"
tput cup 11 20
echo -e " 2: ${BOLD} UPDATESTATUS ${NORMAL}"
tput cup 13 20
echo -e " 3: ${BOLD} DISPLAY ${NORMAL}"
tput cup 15 20
echo -e " 4: ${BOLD} DELETE ${NORMAL}"
fi
error_flag=0 # reset the error flag
tput cup 17 20
echo -e " Enter yout chioce> _ \b\c"
read choice
#
# This case constuct for checking the user selection
#
case $choice in
0)
show_gui
;;
1)
add_record # call EDIT progran
;;
2)
update_record # call UPDATE program
;;
3)
display_record # call DISPALY program
;;
4)
delete_record # call DELETE program
;;
*)
show_error 20 10 # call the ERROR program
tput cup 20 01
tput ed # reset the cursor
error_flag=1 # set the error flag to indicate
;;
esac
done
continue
}
# ------------------------mutil_report_record---------------------
#
# LINUX Library
# mutil_report_record: This program is hte main for the REPORTS menu.
# It shows the reports menu and invokes the
# approriate program accroding to the user
# selection.
#
mutil_report_record(){
error_flag=0 # initialize the error flag.
while true
do
if [ $error_flag -eq 0 ] # check for the error
then
tput clear
tput cup 05 10
echo -e " LINUX Library . ${BOLD} REPORTSMENU ${NORMAL} "
tput cup 07 20
echo -e " 0: ${BOLD} RETURN ${NORMAL} to the Main Menu"
tput cup 9 20
echo -e " 1: Stored by ${BOLD} TITLES ${NORMAL} "
tput cup 11 20
echo -e " 2: Stored by ${BOLD} AUTHORS ${NORMAL} "
tput cup 13 20
echo -e " 3: Stored by ${BOLD} CATEGORY ${NORMAL} "
fi
error_flag=0
tput cup 17 10
echo -e " Enter your chioce > _ \b\c"
read choice
#
# This case construct for checking the user selection.
#
case $choice in # check user input
0)
show_gui
;;
1)
report_record_no 1
;;
2)
report_record_no 2
;;
3)
report_record_no 3
;;
*)
show_error 20 10
tput cup 20 01
tput ed
error_flag=1
;;
esac
done
}
# ------------------------------show_prompts--------------------------
#
# LNIUX Library
# show_prompts: This program will show some prompts of the LIB application
# and then the user press any key to continue.
#
show_prompts(){
tput clear # clear screem
tput cup 10 10
echo -e " ${BOLD}Super Duper LINUX Library" # show the title in bold
tput cup 12 10
echo -e "${NORMAL} This is the LINUX Library application"
tput cup 14 10
echo -e " Please enter any key to continue..._\b\c"
read answer # read the user input
}
# -------------------------------show_gui-----------------------------
#
# Show the title and a brief message befor showing the main meun.
#
show_gui(){
error_flag=0 # initialize the error flag,
# indicating no error
while true
do
if [ $error_flag -eq 0 ] # check for the error
then
tput clear
tput cup 5 10
echo " LINUX Library . ${BOLD}MAIN MENU ${NORMAL}"
tput cup 7 20
echo " 0: ${BOLD} EXIT ${NORMAL} this program"
tput cup 9 20
echo " 1: ${BOLD} EDITE ${NORMAL} Menu"
tput cup 11 20
echo " 2: ${BOLD} REPORTS ${NORMAL} Menu"
error_flag=0 # reset the error flag
fi
tput cup 13 10
echo -e " Entry your choice > _\b\c "
read choice # read user choice
#
# This case construct for checking the user selection.
#
case $choice in # check user input
0)
tput clear
exit 0
;;
1)
edit_recorde
continue
;;
2)
mutil_report_recorde
continue
;;
*)
show_error 20 10
;;
esac
done
contune
}
# --------------------------------main---------------------------------
show_prompts
show_gui
# --------------------------------end----------------------------------
虽然shell不是linux/unix/red hat等unix OS （Operating System）家族的核心组成部分，但是shell绝对是一功能强大的工具。在shell环境下，你可以编写很小的，很smart的程序，也可以编写大型的脚本。通过shell你可以完成计算机高级语言，比如C，所能实现的功能。而且很多时候，你的shell代码要比用C等高级程序开发语言编写的具有相同功能的程序的代码更简洁、更简单、更灵活、更实用。当然了，shell的最大的缺陷就是他只能在UNIX族操作系统上得到应用。它具有和windows操作系统下的.bat一样的实用性。Shell给用户一个执行操作命令的接口外就是这个功能强大的编辑、解释脚本的功能了。
Shell提供了一整套的与之相匹配的语法。之中有while语句，也有if、case、until、for 等结构，但是其实现法方式很高级语言中的定义出入很大。就拿for 语句为例吧。
for 的接单语言结构：
for variable in values
do
statements
done (注意：带黑体的是关键字)
我们可以利用for结构来处理一组可以由任意的字符串组成的集合。在程序里可以简单的把全体字符串豆类出来，更常见的做法是把它与shell对文件名的通配符扩展结合在一起使用。
下面是使用固定字符串的for循环脚本：
#! /bin/sh
for prempt in Hello world I am Today
do
echo $prempt
done
exit 0
脚本的运行结果为：
Hello
world
I
am
Today
如果把for prempt in Hello world I am Today改为for prempt in "Hello world I am Today" 则程序的圆形结果将是：Hell world I am Today.加上引号是在字符串里保留空客的唯一办法了。
在shell里也许用户编写一般的脚本之外，还也许用户定义函数，如果你需要编写较大的脚本程序时，使用自定义函数比较明智的做法，因为你可以通过函数来构造自己喜欢的代码。
在shell里定义函数的方式很简单，只要写出函数的名字，然后在后面加一组空括号"()",最后添加一对花括号就行了。如下：
function_name(){
statements
}
在程序中涉及函数调用时，只需要调用函数的名字就行了。很简单吧。还想提一点建议（这对初接触shell的朋友可能会有一点用处）：考虑到程序的可移植性，你可以用printf语句代替echo语句。因为printf是国际自由软件基金会（Free Software Foundation）的GNU项目的一个标准，在不同版本的UNIx下都有这一条语句。而echo则不同，在不同的厂商的产品中实现方式可能会不一样。
本文旨在于给初学shell的朋友有一点指示和建议，希望能够给大家一点帮助。
