pear默认的目录与文件结构
1. Installation base ($prefix) : /opt/local
2. Temporary directory for processing : /tmp/pear/install
3. Temporary directory for downloads : /tmp/pear/install
4. Binaries directory : /opt/local/bin
5. PHP code directory ($php_dir) : /opt/local/share/pear
6. Documentation directory : /opt/local/docs
7. Data directory : /opt/local/data
8. User-modifiable configuration files directory : /opt/local/cfg
9. Public Web Files directory : /opt/local/www
10. System manual pages directory : /opt/local/man
11. Tests directory : /opt/local/tests
12. Name of configuration file : /opt/local/etc/pear.conf