为什么名为core的文件在这里？我可以删除它吗？

ls -lh
total 37M
-rw-rw-r--  1 hugemeow pg   16 2012-03-04 04:22 a.php
-rw-------  1 hugemeow pg  30M 2012-10-16 10:41 core   // this is the large file
-rw-r--r--  1 hugemeow pg  397 2012-01-26 07:53 index.php
-rw-r--r--  1 hugemeow pg  17K 2012-01-26 07:53 license.txt
-rw-r--r--  1 hugemeow pg 9.0K 2012-01-26 07:53 readme.html
-rw-rw-r--  1 hugemeow pg 7.4M 2012-09-22 02:27 tags
-rw-r--r--  1 hugemeow pg 4.2K 2012-01-26 07:53 wp-activate.php
drwxr-xr-x 10 hugemeow pg 4.0K 2012-10-11 08:37 wp-admin
-rw-r--r--  1 hugemeow pg  40K 2012-01-26 07:53 wp-app.php
-rw-r--r--  1 hugemeow pg  274 2012-01-26 07:53 wp-blog-header.php
-rw-r--r--  1 hugemeow pg 3.9K 2012-01-26 07:53 wp-comments-post.php
-rw-r--r--  1 hugemeow pg 3.2K 2012-01-26 07:53 wp-config-sample.php
-rw-r--r--  1 hugemeow pg 3.6K 2012-10-11 08:37 wp-config.php
-rw-r--r--  1 hugemeow pg 3.5K 2012-03-14 17:08 wp-config.php_bak0
drwxr-xr-x  8 hugemeow pg 4.0K 2012-12-01 04:12 wp-content
-rw-r--r--  1 hugemeow pg 2.7K 2012-01-26 07:53 wp-cron.php
drwxr-xr-x  8 hugemeow pg 4.0K 2012-09-22 02:35 wp-includes
-rw-r--r--  1 hugemeow pg 2.0K 2012-01-26 07:53 wp-links-opml.php
-rw-r--r--  1 hugemeow pg 2.5K 2012-01-26 07:52 wp-load.php
-rw-r--r--  1 hugemeow pg  28K 2012-01-26 07:53 wp-login.php
-rw-r--r--  1 hugemeow pg 7.6K 2012-01-26 07:53 wp-mail.php
-rw-r--r--  1 hugemeow pg  413 2012-01-26 07:53 wp-pass.php
-rw-r--r--  1 hugemeow pg  334 2012-01-26 07:53 wp-register.php
-rw-r--r--  1 hugemeow pg 9.7K 2012-01-26 07:53 wp-settings.php
-rw-r--r--  1 hugemeow pg  19K 2012-01-26 07:53 wp-signup.php
-rw-r--r--  1 hugemeow pg 3.7K 2012-01-26 07:52 wp-trackback.php
-rw-r--r--  1 hugemeow pg 3.2K 2012-01-26 07:53 xmlrpc.php


file core
core: ELF 64-bit LSB core file x86-64, version 1 (SYSV), SVR4-style, from \'php5.cgi\'