参考：http://stackoverflow.com/questions/22934080/how-to-downgrade-to-perl-5-10-1
Perlbrew will allow you to install multiple versions of Perl as user installed Perls.
安装perlbrew
apt-get install perlbrew
To install a particular version of Perl:
perlbrew install 5.10 # I'm installing Perl 5.10!
安装perl前需要建立文件夹:~/perl5/perlbrew/dists和:~/perl5/perlbrew/bulid
To switch from one version of Perl to another:
perlbrew use 5.10 # Use this version in the current shell
or
perlbrew switch 5.10 # This is now your default version of Perl
Linux系统入门学习：Perl中本地时间和UNIX时间戳间相互转换：http://www.linuxdiyf.com/linux/10732.html
Ubuntu升级Perl：http://www.linuxdiyf.com/linux/5169.html