在默认安装安装的mac下没有找到tree命令，找了一下原来有个比较流氓的解决办法：
find . -print | sed -e 's;[^/]*/;|____;g;s;____|; |;g'这个命令行跑起来类似平常tree的效果，比如：
.
|____extra
| |____httpd-autoindex.conf
| |____httpd-dav.conf
| |____httpd-default.conf
| |____httpd-info.conf
| |____httpd-languages.conf
| |____httpd-manual.conf
| |____httpd-mpm.conf
| |____httpd-multilang-errordoc.conf
| |____httpd-ssl.conf
| |____httpd-userdir.conf
| |____httpd-vhosts.conf
|____httpd.conf
|____magic
|____mime.types
|____original
| |____extra
| | |____httpd-autoindex.conf
| | |____httpd-dav.conf
| | |____httpd-default.conf
| | |____httpd-info.conf
| | |____httpd-languages.conf
| | |____httpd-manual.conf
| | |____httpd-mpm.conf
| | |____httpd-multilang-errordoc.conf
| | |____httpd-ssl.conf
| | |____httpd-userdir.conf
| | |____httpd-vhosts.conf
| |____httpd.conf
|____other
| |____bonjour.conf
| |____php5.conf
|____users 写一个alias到~/.bash_profile里，就更方便了:
alias tree="find . -print | sed -e 's;[^/]*/;|____;g;s;____|; |;g'"