可以提高Mac OS 10.7（OS X Lion）中ulimit参数的硬限制吗？

不幸的是，在尝试删除以前的核心转储时，我将核心文件大小硬限制设置为0。有没有办法更改ulimit参数的硬限制

host-101-178:Labs evan$ ulimit -c 0
host-101-178:Labs evan$ ulimit -c 1000000
-bash: ulimit: core file size: cannot modify limit: Operation not permitted
host-101-178:Labs evan$ ulimit -c unlimited
-bash: ulimit: core file size: cannot modify limit: Operation not permitted
host-101-178:Labs evan$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
file size               (blocks, -f) unlimited
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 2560
pipe size            (512 bytes, -p) 1
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 709
virtual memory          (kbytes, -v) unlimited
host-101-178:Labs evan$ ulimit -c unlimited
-bash: ulimit: core file size: cannot modify limit: Operation not permitted

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注销并重新登录，hard coredumpsize限制将恢复为默认值。使用

ulimit -S -c

更改软限制。

sysctl-a | grep core的输出说明了什么？