added instructions for installing prerequisites.

README.md

@@ -1,7 +1,60 @@
 # lynis_report
 [![Build Status](https://travis-ci.org/d4t4king/lynis_report.svg?branch=master)](https://travis-ci.org/d4t4king/lynis_report)
 
-Manageable report from lynis text output.
+Manageable report from lynis text output. Currently available report formats: HTML, PDF, Microsoft Excel (XLSX)\*.
+
+If you want to be able to use the PDF or Excel output formats, you must install some additional software.  As is, the modules are required regardless of whether you use these features or not.  Attempts are being made to change that behavior.
+
+## Instriuctions for pre-requisite installation:
+
+### For Debian/Ubuntu
+```(as root)
+apt update							# versions prior to 16.04 LTS should use 'apt-get'
+apt -y install htmldoc
+
+pushd /tmp/
+wget http://search.cpan.org/CPAN/authors/id/M/MF/MFRANKL/HTML-HTMLDoc-0.10.tar.gz
+tar xvf HTML-HTMLDoc-0.10.tar.gz
+pushd HTML-HTMLDoc-0.10
+perl Makefile.PL
+make && make install
+popd
+wget http://search.cpan.org/CPAN/authors/id/J/JM/JMCNAMARA/Excel-Writer-XLSX-0.95.tar.gz
+tar xvf Excel-Writer-XLSX-0.95.tar.gz
+pushd Excel-Writer-XLSX-0.95
+perl Makefile.PL
+make && make install
+popd
+popd
+```
+### For RHEL/CentOS/Fedora
+```(as root)
+yum -y install htmldoc perl-Excel-Writer-XLSX
+pushd /tmp/
+wget http://search.cpan.org/CPAN/authors/id/M/MF/MFRANKL/HTML-HTMLDoc-0.10.tar.gz
+tar xvf HTML-HTMLDoc-0.10.tar.gz
+pushd HTML-HTMLDoc-0.10
+perl Makefile.PL
+make && make install
+popd
+popd
+```
+
+### for Gentoo
+```(as root)
+emerge -av1 app-text/htmldoc dev-perl/HTML-HTMLDoc 
+
+pushd /tmp/
+wget http://search.cpan.org/CPAN/authors/id/J/JM/JMCNAMARA/Excel-Writer-XLSX-0.95.tar.gz
+tar xvf Excel-Writer-XLSX-0.95.tar.gz
+pushd Excel-Writer-XLSX-0.95
+perl Makefile.PL
+make && make install
+popd
+popd
+
+
+\* It's possible that the Excel format will load for LibreOffic Calc, but this is currentl untested.  YMMV.
 
 ## Help Statement
 ```