Shell Programming and Scripting

Hey guys, i just started shell programming and i have a question. I am working on a simple inventory project and one of the problems which i am unable to solve would be how i am going to extract the data i need from a text file(which will be my database) and then put it inside the executable to be edited or displayed if needed. After it is edited, it needs to be stored in the same file again.

For example, in my text file, which is suppose to be my database , the information will be like this

Name : Price : Quantity
Persia : 30 :40
Shall : 26 : 31

Does anybody know how i code to extract this information from the file(database.txt) and then apply it in the shell script to be displayed , edited or deleted? if there are changes , it has to be saved back into the same file. Hope somebody can enlighten me on this. Thanks.

we all know how. but you should give it a shot and then ask why your script doesn't work. here's a hint, to start you off.

Code:

grep "^Persia :" my_data_file | read name junk price more_junk quantity

hmm, how about grep "persia" data_file_name ? would not this be enough to pull out the data? how come there is a need for a read command?

It is enough to pull out the data but then you need to put it into variables, which can be done through the read statement.

Okay, i am having problems understanding this part. For example, if i were to a new list if items, how do i store it into variables?

Code:

function press_1
{
Number=
echo -n "Title : "
read number
if grep -q "$number" Hello1  ; then
echo "Book Exist"
fi
}

From here on, i was thinking of using an else statement , and then using > to store it back into the Hello1 file , which is the database file. but i think i would have a problem later on when i try to continue storing information about the new book's price and quantity. how do i go about with this problem? i know it has something to do with storing it into variables , but how do i get it to save the information inside the database file in order?

hmmm... in all fairness, I think you may need to review chapter 1 again.

but here's some help:

Code:

function press_1
{
### ksh variables are case sensitive.
### prompt should match variable name or vice versa
### start practicing useful naming conventions.

number=
echo -n "Number: "
read number
if grep -q "$number" data_file  ; then
  echo "Book Exists"
  return
fi

### append and sort information and put back in file
(
echo $number
cat data_file
) | sort > temp_file
/bin/mv temp_file data_file
  
return
}