How to truncate the second column from a dot (.)?

Question

INPUT:

10.175.192.16   vgxyxgf.de.foo.net  asdf    34efg
10.175.192.17   sdtds.de.foo.net    xyyxv   e5432
10.175.243.20   asdfycfb.us.foo.net dfvasf  34525

OUTPUT:

10.175.192.16   vgxyxgf
10.175.192.17   sdtds
10.175.243.20   asdfycfb

How can I make the OUTPUT? Like "awk '{SOMEMAGIC}' foo.txt

So I have the "INPUT" and I need a /etc/hosts file style OUTPUT... :\

Answer 1

With awk

awk '{sub(/\..*/,"",$2);$0=$1 "  "$2}1' foo.txt

With sed

sed 's/^\(\([^.]*\.\)\{4\}\).*$/\1/;s/\.$//' foo.txt

Answer 2

Just for fun, here's a non-awk, non-sed answer:

cut -f1-4 -d. foo.txt

Answer 3

Another awk solution, analogous to Steven's cut answer:

awk -F. -v OFS=. '{print $1, $2, $3, $4}' filename

Uses dots as the field separator, and prints the first 4 fields dot-separated.