Read CSV column value based on column name

Shell Programming and Scripting
1

Hi All,

I am newbie to Unix I ve got assignment to work in unix

can you please help me in this regard

There is a sample CSV file
"Username", "Password"
"John1", "Scot1"
"John2", "Scot2"
"John3", "Scot3"
"John4", "Scot4"

If i give the column name as Password and row number as 4 the result I should get '

'Scot3'

can you please help me in writing shell script for the above

Thanks
John

2

What have you tried so far?

3

I'm assuming this is homework?

First, do you understand how to pass arguments to your script? Do you know what $1, $2 are inside your script?

Next, you need to know how to extract a specific line by number. I realize that the man pages of "sed" are confusing, so to get you going, try

sed -n '4p'

Finally, you need to know how to extract the specific column you want, How will you do that? There are at least two general ways to approach that:

You could build a table that matches column names to a number. Your script would have something like

if [ $1 = "Username" ]
then
Column=1
elif  [ $1 = "Password" ]
then
Column=2
fi
echo $Column

More flexible would be if your script looked up the desired index by examining the first line itself. A crude method:

read line
Wanted=$1
set $line
if [ $Wanted = $1 ]
then
Column=1
...

There are more clever ways to do that - Google for "Awk Associative Arrays" and see if that gives you any ideas in this vein.

I hope this gets you started. Let's see you write some code and we can help you over the rough spots.

4

Thank Tony ,

I have tried the following code giving error , please do the needful
John.csv is the file name

If i give the column name as Password and row number as 4 the result I should get '

'Scot3'

cat John.csv if [ $1 = "Username" ]
then
  Column=1
elif  [ $1 = "Password" ]
then
  Column=2
fi
echo $Column
read line
Wanted=$1
set $line
if [ $Wanted = $1 ]
then
  Column=1
else 
  echo "Hello"
fi

Thanks and Regards,
John