Extract specific words from a line

Question

I hope someone here can help me. I have a line in a text file looking like this:

Jan  8 14:12:56 kernel: SRC=1.2.3.4 DST=255.255.255.255 LEN=104 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=44224 DPT=14000 LEN=84

I want to extract the words starting with SRC=, PROTO= and DPT=. My goal is to end up with a line looking something like this:

1.2.3.4 UDP 14000

I would prefer the solution being bash using sed, awk or similar if possible.

Answer 1

Use Sed with groups:

sed -r 's/.*SRC=(\S+).*PROTO=(\S+).*DPT=(\S+).*/\1 \2 \3/'

Answer 2

One way using awk:

awk 'BEGIN { FS = "[ =]" } { print $7, $22, $26 }' infile

Output:

1.2.3.4 UDP 14000