UNIX for Dummies Questions & Answers

Hi All,

contents of my file is like this:

xxx xxx1 N N N 0
yyy yyy1 Y N N 0

i want to replace 1st N of xxx xxx1 N N N 0 line with Y.
i. e i want the output like this:
xxx xxx1 Y N N 0

how can i do this?
please help.
Thanks

Here is one way to do it

Code:

sed -e "s/xxx xxx1 N/xxx xxx1 Y/g" input.txt

If you want to generalize it, you need to show us a little bit more of the input.

If you exactly knew the occurence of charcter that you need to replace....

Code:

$ echo xxx xxx1 N N N 0 | sed 's/N/Y/1'
xxx xxx1 Y N N 0

thanks..
Both are working.
but how to do if i dont know the exact position of the N, i mean ist time i need to replace 1st N, second time may be 2nd N.
and also i dnt know xxx xxx1 and all. from a file i need to fetch a particular row and i need to replace particular N.

how do i do dat?

It doesn't matter... the above code of mine replace the first occurence of N with Y ... you can change it to whatever you want... to replace the 2nd N

Code:

sed 's/N/Y/2'  filename

If you are still not convinced post a sample input and output

This is working fine. But this will replace the 'N' present in other rows also.

my file contains
xxx xxx1 N N N 0
yyy yyy1 Y N N 0

i want output as xxx xxx1 Y N N 0
yyy yyy1 Y N N 0
i want to replace N from one particular row at a time.
i did like this
grep xxx file | sed 's/N/Y/1'
this will change xxx xxx1 Y N N 0 but i want yyy yyy1 Y N N 0 row also.
what changes i need to do?

sed '1s/N/Y/1' filename

Thanks,
Shahnaz.