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

Since awk and perl are closely related...

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Perl equivalents of @Dennis's awk solutions:

To print the second line:
perl -ne 'print if $. == 2' file

To print the second field:
perl -lane 'print $F[1]' file

To print the third field of the fifth line:
perl -lane 'print $F[2] if $. == 5' file

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Perl equivalent of @Glenn's solution:

Print the j'th field of the i'th line

perl -lanse 'print $F[$j-1] if $. == $i' -- -i=5 -j=3 file

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Perl equivalents of @Hai's solutions:

if you are looking for second columns that contains abc:

perl -lane 'print if $F[1] =~ /abc/' foo

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

perl -lane 'print $F[2] if $F[1] =~ /abc/' foo

... and for a particular line number:

perl -lane 'print $F[2] if $F[1] =~ /abc/ && $. == 5' foo

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-l removes newlines, and adds them back in when printing
-a autosplits the input line into array @F, using whitespace as the delimiter
-n loop over each line of the input file
-e execute the code within quotes
$F[1] is the second element of the array, since Perl starts at 0
$. is the line number