This script finds all mail hosts found in the exim mainlog results file. It then creates one log file per host with potential error messages. Useful for debugging exim mail server problems.

for i in `cat mainlog | sed -n 's/.*=>.*H=\([a-zA-Z0-9.]*\)\(.*\)/\1/p' | sort -u `; do 
    cat mainlog | grep $i | grep -v '=>' > log.$i
done