On CentOS 4 I can't view the mailq man page. I installed postfix and removed sendmail.
# LANG=en_US man mailq fopen: No such file or directory Cannot open man page /usr/share/man/man1/sendmail.1.gz No manual entry for mailq
# zcat /usr/share/man/man1/mailq.postfix.1.gz .so man1/sendmail.1
Solved replacing with ".so man1/sendmail.postfix.1".
Has this little typo to be reported in the CentOS Bug Tracker?