Uma solução usando sed
:
sed -n '$ { s/^\s*/Bytes Sent /; s/\([0-9]\)[ ]/\n/; s/\(\n\)\s*/Bytes Received /; p }' infile
Explicação:
-n # Disable printing lines.
$ # In last line...
s/^\s*/Bytes Sent / # Substitute all spaces from the beginning with literal string 'Bytes Sent'
s/\([0-9]\)[ ]/\n/ # Substitute first match of a space after a number with a new line.
s/\(\n\)\s*/Bytes Received / # Substitute all space after the new line with literal string 'Bytes received'
p # Print this line (two lines after the included '\n')
Resultado:
Bytes Sent 3084237796552
Bytes Received 13027195853643