Using awk to filter text files for specific columns of information

Linux

Using awk to filter specific information.
# print column one using space as a separator

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

# print column four using : as a separator

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

Use grep -i for case insensitive search.