A question for a programmer
I am going through a book on Linux programming. One of the examples does
not work. I was wondering if someone could take a look at the script and
see why it doesn't work. The program is exactly like the example from the
book, in fact I downloaded it from www.wrox.com the
publisher of the book Beginning Linux Programming. The part that doesn't
work is the list_tracks section.
Thank You,
Keith
nfn11988@naples.net
#!/bin/sh
# Very simple example shell script for managing a CD collection.
# Copyright (C) 1996 Wrox Press.
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License 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 useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.
# 675 Mass Ave, Cambridge, MA 02139, USA.
# A few global variables we need. Put them here for clarity.
menu_choice=""
current_cd=""
title_file="title.cdb"
tracks_file="tracks.cdb"
temp_file=/tmp/cdb.$$
trap 'rm -f $temp_file' EXIT
get_return() {
echo -e "Press return \c"
read x
return 0
}
get_confirm() {
echo -e "Are you sure? \c"
while true
do
read x
case "$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 $* >> $tracks_file
return
}
add_record_tracks() {
echo "Enter track information for this CD"
echo "When no more tracks enter q"
cdtrack=1
cdttitle=""
while [ "$cdttitle" != "q" ]
do
echo -e "Track $cdtrack, track title? \c"
read tmp
# case "$tmp" in
# "") continue
# ;;
# *,*) echo "Sorry, no commas allowed"
# continue
# ;;
# esac
cdttitle=${tmp%%,*}
if [ "$tmp" != "$cdttitle" ]; then
echo "Sorry, no commas allowed"
continue
fi
if [ -n "$cdttitle" ]; then
if [ "$cdttitle" != "q" ]; then
insert_track $cdcatnum,$cdtrack,$cdttitle
fi
else
cdtrack=$((cdtrack-1))
fi
cdtrack=$((cdtrack+1))
done
}
# This allows adding of a new CD
add_records() {
# Prompt for the initial information
echo -e "Enter catalog number \c"
read tmp
cdcatnum=${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 titles file
# get_confirm && insert_title $cdcatnum,$cdtitle,$cdtype,$cdac
if get_confirm ; then
insert_title $cdcatnum,$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=$1
linesfound=$(wc -l $temp_file)
case "$linesfound" in
0) echo "Sorry, nothing found"
get_return
return 0
;;
1) ;;
2) echo "Sorry, not unique."
echo "Found the following"
cat $temp_file
get_return
return 0
esac
# if [ "$linesfound" = "0" ]; then
# echo "Sorry, nothing found"
# get_return && return 0
# fi
# if [ "$linesfound" != "1" ]; then
# echo "Sorry, not unique."
# echo "Found the following ..."
# cat $temp_file
# get_return && return 0
# fi
# cdcatnum=$(cut -f 1 -d , $temp_file)
IFS=","
read cdcatnum cdtitle cdtype cdac < $temp_file
IFS=" "
# if [ "$cdcatnum" = "" ]; then
if [ -z "$cdcatnum" ]; then
echo "Sorry, could not extract catalog field from $temp_file"
# cat $temp_file
get_return
return 0
fi
# cdtitle=$(cut -f 2 -d , $temp_file)
# cdtype=$(cut -f 3 -d , $temp_file)
# cdac=$(cut -f 4 -d , $temp_file)
echo
echo Catalog number $cdcatnum
echo $cdtitle
echo $cdtype
echo $cdac
echo
get_return
if [ "$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
# cat $temp_file > $tracks_file
echo
add_record_tracks
}
fi
return
}
count_cds() {
num_titles=$(wc -l $title_file)
num_tracks=$(wc -l $tracks_file)
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
set $(wc -l $temp_file)
num_tracks=$1
if [ "$num_tracks" = "0" ]; then
echo no tracks found for $cdtitle
else {
echo
echo "$cdtitle :-"
echo
cut -f 2- -d , $temp_file
echo }| more
fi
fi
get_return
return
}
# Main routine starts here
#
# get the files in a known state
rm -f $temp_file
if [ ! -f $title_file ]; then
touch $title_file
fi
if [ ! -f $tracks_file ]; then
touch $tracks_file
fi
# Now the application proper
clear
echo
echo
echo "Mini CD manager"
sleep 3
quit=n
while [ "$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
--
Unsubscribe? mail -s unsubscribe debian-user-request@lists.debian.org < /dev/null
Reply to: