       ulimit [ -Hacdflmnopstv ] [ limit ]
              Set or display a resource  limit.  When  setting  a
              limit  it  will  apply to the children of the shell
              but not to the shell itself. The value of limit can
              be  a  number  in  the  unit specified below or the
              value unlimited.  If the H flag is given  use  hard
              limits instead of soft limits.
              -a     Lists all of the current resource limits.
              -c     The number of 512-byte blocks on the size of
                     core dumps.
              -d     The number of K-bytes on  the  size  of  the
                     data segment.
              -f     The number of 512-byte blocks on the size of
                     files written.
              -l     The number of K-bytes on the size of locked-
                     in memory.
              -m     The  number of K-bytes on the size of physi-
                     cal memory.
              -n     The number of file descriptors.
              -o     The number of open files.
              -p     The number of processes.
              -s     The number of K-bytes on  the  size  of  the
                     stack.
              -t     The number of CPU seconds to be used.
              -v     The number of K-bytes on the size of virtual
                     memory.
