       ulimit [ -SHacdflmnpstv ] [ limit ] ...
              Set or display resource limits of the shell and the
              processes started by the shell.  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.  If the -S flag is
              given together with the -H flag set both  hard  and
              soft limits.  If no options are used, the file size
              limit (-f) is assumed.  If  limit  is  omitted  the
              current   value  of  the  specified  resources  are
              printed.  When more than one  resource  values  are
              printed  the  limit name and unit is printed before
              each value.
              -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 open file descriptors.
              -s     The  number  of  K-bytes  on the size of the
                     stack.
              -t     The number of CPU seconds to be used.

              -u     The number of  processes  available  to  the
                     user.
              -v     The number of K-bytes on the size of virtual
                     memory.
