File Field Replacement, Assigning Fields to Variables, Lists/Arrays?

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02-19-2011

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File Field Replacement, Assigning Fields to Variables, Lists/Arrays?

Okay, I've made threads on extracting fields and comparing strings in separate files in .csv's. I've written the following code with intentions of learning more.

I just want this one question answered: How can I assign fields from a file(comma separated) to variables?

My goal is to check whether or not a user is driving a car. If he is, he will not be capable of driving others. If he is not, he will be capable of driving one.

So first off, here's a sample cars.csv file I made:
The fields separated by commas represent ID number of driver, car model, brand, make, and a boolean 0/1 to see whether or not the car is being driven, respectively.

Code:

#cars.csv
000000,Protege,Mazda,2003,0
000000,Pathfinder,Nissan,1997,0
123456,Corvette,Chevrolet,1976,1
000000,Jimmy,GMC,1994,0
535712,Carrera,Porsche,1

Next, here is a sample drivers.csv listing the drivers:
The fields in this file are ID number of driver, name of driver, and a boolean 0/1 to check if the user is driving a car, respectively.

Code:

#drivers.csv
123456,John,1
125639,Jack,0
967381,Bob,0
535712,Ben,1
649264,Brian,0

This file, garage.sh allows the user to be selected. I used case for the first part as I don't know how to do what I am asking for..yet.

Code:

#garage.sh
echo "Who are you? (select 1,2,3,etc)"
echo 1. John
echo 2. Jack
echo 3. Bob
echo 4. Ben
echo 5. Brian
read name
case $name in 
	1)
		IDnum="123456";;
	2)
		IDnum="125639";;
	3)
		IDnum="967381";;
	4)
		IDnum="535712";;
	5)
		IDnum="649264";;
	*)
		echo Invalid command;;
esac
echo " "
echo " "
echo Enter one of the commands below:
echo 1. Drive a car
echo 2. Park a car
echo 3. Check user status
echo 4. Quit
while :
do
        read command
        case $command in
                1)
                        `sh drive.sh "$IDnum"`;;
                2)
                        `sh park.sh "$IDnum"`;;
                3)
                        `sh userstatus.sh "$IDnum"`;;
                4)
                        break;;
                *)
                        echo Invalid command;;
        esac
done

Okay, so what I want to do is try select a driver and select a command. I don't want to ask how to do a lot as I want to learn to do the others from what you tell me.

So, for example, I could compare the IDnum in cars.csv with the IDnum in drivers.csv and output it with something like this:

Code:

join -t, -11 -21 -o2.2,1.2,1.3,1.4,1.1 <(sort cars.csv) <(sort drivers.csv) > output.csv

Question 1:
How would I do the above comparison but assign all fields to different variables? (ie. $model=1.2, $year=1.4, etc)

Quote:

Question 2:
How would I make it output a list to the screen like the one below and allow users to select which car to drive(preferably using case so the code flows)?

Code:

#only cars that are not being driven
1. 2003 Mazda Protege
2. 1997 Nissan Pathfinder
3. 1994 GMC Jimmy

Figured this one out on my own using the following:

Code:

count=0
awk -F, '{ if ($1 == "000000") print $4, $3, $2}' cars.csv | while read line
do
        count=$(($count + 1))
        echo $count. $line
done
echo " "
echo "Which car would you like to drive?"
read car

Still need to know how to set things to values and write them back in

Quote:

Question 3:
Conversely to question 1, how would I write/replace fields in the .csv's with variables in the script? (I think I could do it using sed?)

EDIT: I think I can just use -tr...but we'll see

Last edited by chickeneaterguy; 02-20-2011 at 05:21 AM..

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