install perl Module
1. search module's package on [Google](https://www.google.com) or [CPAN Search Site](http://search.cpan.org/)
2. download packages into ~/Downloads if it exists
3. Unpack the CPAN Perl module:
* cd ~/Downloads
* tar -zxvf ./perl-module.tar.gz
5. specify the installation into ~/perl5
* cd perl-module/
* perl Makefile.PL PREFIX=~/perl5
* make
* make test
* make install
6. append ~/.bashrc: export PERL5LIB="$HOME/perl5/:$PERL5LIB";
an alternative way to install perl module -- [cpanm](https://stackoverflow.com/questions/2980297/how-can-i-use-cpan-as-a-non-root-user)
1. install cpanm
* wget -O- http://cpanmin.us | perl - -l ~/perl5 App::cpanminus local::lib
* eval `perl -I ~/perl5/lib/perl5 -Mlocal::lib`
* echo 'eval `perl -I ~/perl5/lib/perl5 -Mlocal::lib`' >> ~/.bashrc
2. then we can install mudules
* cpanm DateTime [--force]
install Sybase
1. install freetds, http://www.freetds.org
* wget http://www.freetds.org/files/current/freetds-current.tar.gz
* tar -zxvf freetds-current.tar.gz
* cd freetds-dev.1.00.339/
* ./configure --prefix=$HOME/freetds
* make
* make install
2. install Sybase module
* wget http://search.cpan.org/CPAN/authors/id/M/ME/MEWP/DBD-Sybase-1.16.tar.gz
* tar -zxvf DBD-Sybase-1.16.tar.gz
* cd DBD-Sybase-1.16/
* export SYBASE=$HOME/freetds
* perl Makefile.PL
* make
* make install
3. install DBI
* cpanm DBI
