CD collection application with shell

文件结构
//title file
Catalog     Title           Type    Composer
CD123     Cool sax        Jazz           Bix
CD234       Classic violin  classical      Bach
//tracks file
Catalog     Track No.       Title
CD123       1               Some jazz
注：数据库使用指定的字段长度限制字段，这里使用分隔符CSV(comma-separated variable)
//相关函数
get_return()
get_confirm()
set_menu_choice()
insert_title()
insert_track()
add_record_tracks()
add_records()
find_cd()
update_cd()
count_cds()
remove_records()
list_tracks()

 

 

1、First copyright information
#!/bin/bash

#Very simple example shell script for managing a CD collection.
#Copyright (C) 1996-2007 Wiley Publishing Inc.

#This program is free software; you can redistribute it and/or modify it
#under the terms of the GNU General Public Licence as published by the
#Free Software Foundation; either version 2 of the License, or (at your
#option) any later version.

#This program is distributed in the hopes that it will be usefull, but
#WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHATABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GUN General
#Public License for more details.

#You should have received a copy of the GNU General Public Licence along
#with this program; if not, write to the Free SoftWare Foundation,Inc.
#675 Mass Ave, Cambridge, MA 02139, USA.

2、定义全局变量，trap Ctrl+C
menu_choice=""
current_cd=""
title_file="title.cdb"
tracks_file="tracks.cdb"
temp_file=/tmp/cdb.$$
trap `rm -f $temp_file` EXIT

3、定义函数
get_return(){
 echo -e "Press return \c"
 read x
 return 0
}
get_confirm(){
 echo -e "Are you sure?\c"
 while true
 do
  read x
  case "$x" in
  y|yes|Y|Yes|YES)
   return 0;;
  n|no|N|No|NO)
  echo
  echo "Cancelled"
  return 1;;
  *) echo "Please enter yes or no";;
 esac
 done
}

set_menu_choice(){
 clear
 echo "Options :-"
 echo
 echo " a)Add new CD"
 echo " f)Find CD"
 echo " c)Count the CDs and tracks in the catalog"
 if [ "$cdcatnum" != "" ];then
  echo " l)List tracks on $cdtitle"
  echo " r)Remove $cdtitle"
  echo " u)Update track information for $cdtitle"
 fi
 echo " q)Quit"
 echo
 echo -e "Please enter choice then press return \c"
 read menu_choice
 return
}

insert_title(){
 echo $*>>$title_file
 return
}
insert_track(){
 echo $*>>$track_file
 return
}

add_record_tracks(){
 echo "Enter track information for this CD"
 echo "When no more tracks enter q"
 cdtrack=1
 cdttitle=""
 while [ "$cdttitle" != "q" ]
 do
  echo -e "Track $cdtrack,track title? \c"
  read tmp
  cdttitle=${tmp%%,*}
  if [ "$tmp" != "$cdttitle" ];then
   echo "Sorry,no commas allowed"
   continue
  fi
  if [ -n "$cdttile"] ; then
   if [ "$cdttitle" != "q" ];then
    insert_track $cdcatum,$cdtrack,$cdttitle
   fi
  else
   cdtrack=$((cdtrack - 1))
  fi
  cdtrack=$((cdtrack + 1))
 done
}

add_records(){
#Prompt for the initial information
 echo -e "Enter catalog name\c"
 read tmp
 cdcatnum=${tmp%%,*}
 echo -e "Enter title\c"
 read tmp
 cdtitle=${tmp%%,*}
 echo -e "Enter type \c"
 read tmp
 cdtype=${tmp%%,*}
 echo -e "Enter artist/composer \c"
 read tmp
 cdac=${tmp%%,*}
#Check that they want to enter the information
 echo About to add new entry
 echo "$cdcatnum %cdtitle %cdtype %cdac"
#If confirmed then append it to the title file
if get_confirm;then
 insert_title $cdcatum,$cdtitle,$cdtype,$cdac
 add_record_tracks
else
 remove_records
fi
return
}

find_cd(){
 if [ "$1" = "n" ];then
 asklist=n
 else
 asklist=y
 fi
 cdcatnum=""
 echo -e "Enter a string to search for in the CD titles\c"
 read searchstr
 if [ "$searchstr" = "" ];then
  return 0
 fi
 grep "$searchstr" $title_file>$temp_file
 set $(wc -l $temp_file)
 linesfound=$1
 case "$linesfound" in
 0) echo "Sorry,nothing found"
  get_return
  return 0
  ;;
 1) ;;
 2) echo "Sorry,not unique."
  echo "Found the following"
  cat $temp_file
  get_return
  return 0
 esac
IFS=","
read cdcatnum cdtitle cdtype cdac < $temp_file
IFS=" "
if [ -z "$cdcatnum" ];then
 echo "Sorry,could not extract catalog field from $temp_file"
 get_return
 return 0
fi

echo
echo Catalog number: $cdcatnum
echo Title:$cdtitle
echo Type:$cdtype
echo Artist/Composer:$cdac
echo
get_return
if [ "$asklist" = "y" ];then
 echo -e "View tracks for this CD? \c"
 read x
 if [ "$x" = "y" ];then
 echo
 list_tracks
 echo
 fi
 fi
 return 1
}

update_cd(){
 if [ -z "$cdcatnum" ];then
  echo "You must select a CD first"
  find_cd n
 fi
 if [ -n "$cdcatnum" ];then
  echo "Current tracks are :-"
  list_tracks
  echo
  echo "This will re-enter the tracks for $cdtitle"
 get_confirm && {
  grep -v "^${cdcatnum}," $tracks_file>$temp_file
  mv $temp_file $tracks_file
  echo
  add_record_tracks
 }
 fi
 return
}

count_cds(){
 set $(wc -l $title_file)
 num_titles=$1
 set $(wc -l $tracks_file)
 num_tracks=$1
 echo found $num_titles CDs,with a total of $num_tracks tracks
 get_return
 return
}

remove_records(){
 if [ -z "$cdcatnum" ];then
  echo You must select a CD first
  find_cd n
 fi
 if [ -n "$cdcatnum" ];then
  echo "You are about to delete $cdtitle"
  get_confirm &&{
  grep -v "^${cdcatnum}," $title_file>$temp_file
  mv $temp_file $title_file
  grep -v "^${cdcatnum}," $tracks_file>$temp_file
  mv $temp_file $tracks_file
  cdcatnum=""
  echo Entry removed
  }
  get_return
 fi
 return
}

list_tracks(){
 if [ "$cdcatnum" = "" ];then
 echo no CD selected yet
 return
 else
 grep "^${cdcatnum}," $tracks_file>$temp_file
 num_tracks=$(wc -l $temp_file)
 if [ "$num_tracks" = "0" ];then
  echo no tracks found for $cdtitle
 else{
  echo
  echo "$cdtitle :-"
  echo
  cut -f 2- -d , $temp_file
  echo
 } | ${PAGER:-more}
 fi
 fi
 get_return
 return
}

rm -f $temp_file
if [ ! -f $title_file ];then
 touch $title_file
fi
if [ ! -f $tracks_file ];then
 touch $tracks_file
fi
#Now the application proper
clear
echo
echo
echo "Mini CD manager"
sleep 1

quit=n
while [ "$quit" != "y" ]; 
do
 set_menu_choice
 case "$menu_choice" in
 a) add_records;;
 r) remove_records;;
 f) find_cd y;;
 u) update_cd;;
 c) count_cds;;
 l) list_tracks;;
 b)
  echo
  more $title_file
  echo
  get_return;;
 q|Q)quit=y;
 *)echo "Sorry,choice not recognized";;
 esac
 done
#Tidy up and leave
rm -f $temp_file
echo "Finished"
exit 0