select row and element in awk

Question

Hi,

I learned that in awk, $2 is the 2nd column. How to specify the ith line and the element at the ith row and jth column?

Thanks and regards!

Answer 1

To print the second line:

awk 'FNR == 2 {print}'

To print the second field:

awk '{print $2}'

To print the third field of the fifth line:

awk 'FNR == 5 {print $3}'

Edit: Here's an example with a header line and (redundant) field descriptions:

awk 'BEGIN {print "Name\t\tAge"}  FNR == 5 {print "Name: "$3"\tAge: "$2}'

There are better ways to align columns than "\t\t" by the way.

Answer 2

To expand on Dennis's answer, use awk's -v option to pass the i and j values:

# print the j'th field of the i'th line
awk -v i=5 -v j=3 'FNR == i {print $j}'

Answer 3

To print the columns with a specific string, you use the // search pattern. For example, if you are looking for second columns that contains abc:

awk '$2 ~ /abc/'

... and if you want to print only a particular column:

awk '$2 ~ /abc/ { print $3 }'

... and for a particular line number:

awk '$2 ~ /abc/ && FNR == 5 { print $3 }'

Answer 4

and how can i print the last row, only? thank you!