Select row and element in awk

Question

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?

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}' 

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.

Use exit to stop as soon as you've printed the desired record if there's no reason to process the whole file:

awk 'FNR == 2 {print; exit}' 

Answer 2

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 }'