How to add a column from a file to another file

Question

I have a file with two columns as

1 1
2 3
3 4

and a file with one column as

6
7
9

I would like to add the

Answer 1

$ pr -mts' ' file1 file2
1 1 6
2 3 7
3 4 9

$ paste -d' ' file1 file2
1 1 6
2 3 7
3 4 9

Answer 2

A pure bash solution can be:

exec 3<twofile
while read x; do read -u 3 y; echo $x $y; done <onefile

Infiles:

cat >onefile <<XXX
1 1
2 3
3 4
XXX
cat >twofile <<XXX
6
7
9
XXX

Output:

1 1 6
2 3 7
3 4 9

Answer 3

awk 'NR==FNR{a[NR]=$0;next}{print a[FNR],$0}' file1 file2

Note: Will work with files of same length. If file lengths' are different, go with sudo_O's solution.

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Just for the heck of it, here is an awk command that I think should simulate paste. Purely for fun though, if I were you I would still go with sudo_O's solution (or may be not!)

awk 'NR==FNR{a[++y]=$0;next}{b[++x]=$0}
END{z=x>y?x:y;while(++i<=z){print a[i],b[i]}}' file1 file2