A.awk B.grep C.cat D.less
A.awk’{print$1}’/var/log/httpd/access_log∣sort B.awk’{print$1}’/var/log/httpd/access_log∣sort∣uniq C.awk’{print$1}’/var/log/httpd/access_log∣sort∣uniq∣wc-l D.awk’{print$1}’/var/log/httpd/access_log