How to print last two columns using awk
AwkAwk Problem Overview
All I want is the last two columns printed.
Awk Solutions
Solution 1 - Awk
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.
Solution 2 - Awk
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"
Solution 3 - Awk
@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
Solution 4 - Awk
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.
Solution 5 - Awk
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
Solution 6 - Awk
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% /