参数说明：
-a All current limits are reported -b The maximum socket buffer size -c The maximum size of core files created -d The maximum size of a process's data segment -e The maximum scheduling priority ( "nice" ) -f The maximum size of files written by the shell and its children -i The maximum number of pending signals -l The maximum size that may be locked into memory -m The maximum resident set size (many systems do not honor this limit) -n The maximum number of open file descriptors (most systems do not allow this value to be set ) -p The pipe size in 512 byte blocks (this may not be set ) -q The maximum number of bytes in POSIX message queues -r The maximum real-time scheduling priority -s The maximum stack size -t The maximum amount of cpu time in seconds -u The maximum number of processes available to a single user -v The maximum amount of virtual memory available to the shell -x The maximum number of file locks -T The maximum number of threads
显示全部信息：
ulimit -a
返回的属性值说明：
core file size //限制内核文件的大小限制 data seg size //最大数据大小限制 scheduling priority //调度优先级 file size //最大文件大小限制 pending signals //信号可以被挂起的最大数，这个值针对所有用户,表示可以被挂起/阻塞的最大信号数量 max locked memory //内存锁定值的限制 max memory size //最大可以使用内存限制 open files //进程打开文件数的限制 pipe size //管道文件大小限制 POSIX message queues //可以创建使用POSIX消息队列的最大值，单位为bytes real-time priority //限制程序实时优先级的范围,只针对普通用户 stack size //限制进程使用堆栈段的大小 cpu time //程序占用CPU的时间,单位是秒 max user processes //限制程序可以fork的进程数，只对普通用户有效 virtual memory //限制进程使用虚拟内存的大小 file locks //锁定文件大小限制