How to print last two columns using awk

Question

All I want is the last two columns printed.

Answer 1

awk '{print $NF-1, $NF}'  inputfile

Note: this works only if at least two columns exist. On records with one column you will get a spurious "-1 column1"

Answer 2

using gawk exhibits the problem:

 gawk '{ print $NF-1, $NF}' filename
1 2
2 3
-1 one
-1 three
# cat filename
1 2
2 3
one
one two three

I just put gawk on Solaris 10 M4000: So, gawk is the cuplrit on the $NF-1 vs. $(NF-1) issue. Next question what does POSIX say? per:

http://www.opengroup.org/onlinepubs/009695399/utilities/awk.html

There is no direction one way or the other. Not good. gawk implies subtraction, other awks imply field number or subtraction. hmm.

Answer 3

@jim mcnamara: try using parentheses for around NF, i. e. $(NF-1) and $(NF) instead of $NF-1 and $NF (works on Mac OS X 10.6.8 for FreeBSD awkand gawk).

echo '
1 2
2 3
one
one two three
' | gawk '{if (NF >= 2) print $(NF-1), $(NF);}'

# output:
# 1 2
# 2 3
# two three

Answer 4

try with this

$ cat /tmp/topfs.txt
/dev/sda2      xfs        32G   10G   22G  32% /

awk print last column
$ cat /tmp/topfs.txt | awk '{print $NF}'

awk print before last column
$ cat /tmp/topfs.txt | awk '{print $(NF-1)}'
32%

awk - print last two columns
$ cat /tmp/topfs.txt | awk '{print $(NF-1), $NF}'
32% /

Answer 5

You can make use of variable NF which is set to the total number of fields in the input record:

awk '{print $(NF-1),"\t",$NF}' file

this assumes that you have at least 2 fields.

Answer 6

Please try this out to take into account all possible scenarios:

awk '{print $(NF-1)"\t"$NF}'  file

or

awk 'BEGIN{OFS="\t"}' file

or

awk '{print $(NF-1), $NF} {print $(NF-1), $NF}' file