Replace a particular field in a particular line with user input using awk

Divyavec · 08-03-2012, 02:05 AM

I have a file called addr_book with the following data

FNAME LNAME ADDRESS PHONE COUNTRY
Harry Williams Virginia 1234 USA
Divya Purush Chennai 2098 India
Smith John Kentucky 1093 USA
Carol Stevens Wisconsin 3410 USa
Smith Williams sydney 5120 Aus
Feena Joseph veitname 1098 -

I have to edit the fname here.User enters the fname and lname of the person whose name i have to edit and also the new fname.With this I have to replace the fname.

I used the following

num1=$(awk -v new1="$lname" -v new="$fname" '($2==new1 && $1==new) {print NR}' addr_book)

echo "Enter the new fname:"
read new1
awk -v n="$choice" -v new="$new1" -v n1="$num1"
'{for (i=1;i<=5;i++) { if(($i=="$n") && (NR=="$n1")) $i="$new";print}' addr_book > addr_book.bak.

It is not giving the desired output...Can Some one help me pls?

Chirel · 08-03-2012, 03:08 AM

Hi,

Code:

fname=Smith
lname=John
newn=Garry
awk -v "lname=$lname" -v "fname=$fname" -v "newn=$newn" '$0 ~ fname" "lname {sub("^"fname,newn); print}' addr_book

grail · 08-03-2012, 04:08 AM

Well I agree with most of the last reply but see no reason to use sub:

Code:

awk -v "lname=$lname" -v "fname=$fname" -v "newn=$newn" '$0 ~ fname" "lname{$1 = newn}1' addr_book

Divyavec · 08-03-2012, 04:19 AM

Thanks a lot to both of you

What if i want to ask the user as which field to edit and edit tat field

echo "Enter the field you want to edit[1,2,3,4,5] :"
echo "1.First_name
2.last_name
3.Address
4.Phone
5.Country"
read choice
echo "Enter the new field:"
read new1

if the user enters 3,i have to edit Address field..Can i use for loop in this case?

Divyavec · 08-03-2012, 05:31 AM

This is the code i am using to achieve the above scenario...But its not working

awk -v "lname=$lname" -v "fname=$fname" -v "newn=$newn" -v "ch=$choice" '$1 ~ fname && $2 ~ lname{for (i=1;i<=5;i++) if (ch==$i) $i = newn}1 ' addr_book

grail · 08-03-2012, 06:28 AM

Depends how much effort you want to put in I guess, here is one direction:

Code:

#!/usr/bin/awk -f

BEGIN{	
    getline list
    split(list, items)
    printf "Please enter first name: "
    getline fname < "-"
    printf "Please enter last name: "
    getline lname < "-"

    print "Select item from list below to be changed (enter corresponding number):"
    for( i = 1; i <= length(items); i++ )
	print i":",items[i]
    printf "> "
    getline num < "-"

    printf "Enter new data: "
    getline change < "-"

    print list
}

$1 == fname && $2 == lname{ $num = change }

1

Divyavec · 08-09-2012, 08:57 AM

@grail

This looks a bit complex.Isnt there a easy way to do this.

Cant we use a for loop like the below

awk -v "lname=$lname" -v "fname=$fname" -v "newn=$newn" -v "ch=$choice" '$1 ~ fname && $2 ~ lname{for (i=1;i<=5;i++) if (ch==$i) $i = newn}1 ' addr_book

grail · 08-09-2012, 09:23 AM

And where did you get all the variables from that you have created, ie lname, fname, newn, choice?

Once you have all the variables set, from mine you would only need:

Code:

$1 == fname && $2 == lname{ $num = change }

Remember I did say:

Quote:

Depends how much effort you want to put in

This a complete script and needs no extra input such as your shell variables (as mentioned above)