查看方法：ulimit -a  软限制

下面是Ubuntu12.04 x64系统下，进程资源限制情况：

core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 63315  信号可以被挂起的最大数
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024      内核可以同时打开的文件描述符的最大值
pipe size            (512 bytes, -p) 8     管道最大使用的空间为  4K
POSIX message queues     (bytes, -q) 819200  消息队列最大使用的内存 800K
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192         进程栈区最大为8M
cpu time               (seconds, -t) unlimited
max user processes              (-u) 63315       用户最大可以启动进程数
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

ulimit -a -H 硬限制

core file size          (blocks, -c) unlimited
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 63315
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 4096
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) unlimited
cpu time               (seconds, -t) unlimited
max user processes              (-u) 63315
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited