Using awk to filter text files for specific columns of information

awk usage

grep 62.8.121.194 /var/log/maillog.1 | awk `{print $1}'

grep 62.8.121.194 /var/log/maillog.1 | awk '{print $1}'

grep 62.8.121.194 /var/log/maillog.1 | awk -F ":" '{print $4}'

grep 62.8.121.194 /var/log/maillog.1 | awk -F ":" '{print $4}' > testrej