substituting a dot (.) with a space (“ ”) awk, sed or grep

Question

I need to go through tcpdump files which have IP addresses followed by their source or destination port in this way: 192.168.1.0.80 to this one: 192.168.1.0 80 .

How can I do this using awk, sed or grep?

Answer 1

With sed :

tcpdump -v -n |
sed -r 's@([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})\.([0-9]{1,5})@\1 \2@g'

EXPLANATION

• -r switch stands for extented regex (I use it to avoid parentheses backslash)
• s@@@ is a substitution skeleton , the delimiter can be anything we want, not only s/// . s/before/after/
• ( group and capture to \\1 (to \\N)
• [0-9]{1,3} any character of: '0' to '9' (between 1 and 3 times (matching the most amount possible))
• \\. a literal '.'
• ) end of a capture
• \\1 and \\2 are the captured stuff
• g modifier stands for all occurences