Ulimit provides control over the resources available to processes
started by the shell, on systems that allow such control. If an
option is given, it is interpreted as follows:
-S
[tab]use the `soft' resource limit
-H
[tab]use the `hard' resource limit
-a
[tab]all current limits are reported
-c
[tab]the maximum size of core files created
-d
[tab]the maximum size of a process's data segment
-e
[tab]the maximum scheduling priority (`nice')
-f
[tab]the maximum size of files written by the shell and its children
-i
[tab]the maximum number of pending signals
-l
[tab]the maximum size a process may lock into memory
-m
[tab]the maximum resident set size
-n
[tab]the maximum number of open file descriptors
-p
[tab]the pipe buffer size
-q
[tab]the maximum number of bytes in POSIX message queues
-r
[tab]the maximum real-time scheduling priority
-s
[tab]the maximum stack size
-t
[tab]the maximum amount of cpu time in seconds
-u
[tab]the maximum number of user processes
-v
[tab]the size of virtual memory
-x
[tab]the maximum number of file locks
If LIMIT is given, it is the new value of the specified resource;
the special LIMIT values `soft', `hard', and `unlimited' stand for
the current soft limit, the current hard limit, and no limit, respectively.
Otherwise, the current value of the specified resource is printed.
If no option is given, then -f is assumed. Values are in 1024-byte
increments, except for -t, which is in seconds, -p, which is in
increments of 512 bytes, and -u, which is an unscaled number of
processes.
