set or display a resource limit
/usr/bin/ulimit -HSacdfmnstv [limit]
This shell script executes the builtin command of the same name
as implemented by the /u95/bin/sh shell.
for more information on this shell.
Use ulimit to set or display a resource limit.
The available resource limits are listed below.
The limit for a specified resource is set when limit is specified.
The value of limit can be a number in the unit specified
below with each resource, or the value unlimited.
The -H and -S options specify whether the hard
limit or the soft limit, respectively, for the given resource is set.
A hard limit cannot be increased once it is set.
A soft limit can be increased up to the value of the hard limit.
If neither the -H nor -S
options is specified, the limit applies to both.
Only a process with SYSOPS privilege can increase a hard
If limit is omitted, the current soft resource limit is
displayed, unless -H is specified to print the hard limit.
When more than one resource is specified, then the limit
name and unit is printed before the value.
Lists all of the current resource limits.
The number of 512-byte blocks on the size of core dumps.
The number of K-bytes on the size of the data area.
The number of 512-byte blocks on files that can be written by the
current process and its child processes (files of any size may be read).
On file systems (such as vxfs file systems) that support large files,
setting this limit to unlimited represents the largest file
size supported on the file system.
The number of K-bytes on the size of physical memory.
The number of file descriptors plus 1.
The number of K-bytes on the size of the stack area.
The number of CPU seconds to be used by each process.
The number of K-bytes for virtual memory.
If no option is given, -f is assumed; that is, you
can specify a limit with or without the preceding
-f option, and both cases are interpreted as an attempt to raise
the file size limit.
Gives the resource-specific limit to use as the new resource limit.
Sets the largest allowable resource limit.
It is necessary to set
limit to the value unlimited
for access to large files (greater than 2GB in size).
``Changing the maximum allowed file size (ulimit)'' in the UnixWare 7 System Handbook
for more information.
The following environment variables affect the execution of
Provide a default value for the internationalization variables
that are unset or null.
If LANG is unset or null, the corresponding value from the
implementation-specific default locale will be used.
If any of the internationalization variables contains an invalid
setting, the utility will behave as if none of the variables
had been defined.
If set to a non-empty string value, override the values of all the
other internationalization variables.
Determine the locale for the interpretation of sequences of bytes of
text data as characters (for example, single- as opposed to multi-byte
characters in arguments).
Determine the locale that should be used to affect the format and
contents of diagnostic messages written to standard error.
The standard output is used when no limit operand is present.
If the current number of blocks is limited, the number of blocks
in the current limit is written to standard output.
An exit code of ``0''indicates successful completion; an
greater than ``0'' indicates that a request for a higher
was rejected or an error occurred.
Since ulimit affects the current shell execution environment,
if it is called in a separate utility execution environment,
such as one of the following:
nohup ulimit -f 10000
env ulimit 10000
it will not affect the file size limit of the caller's
Once a limit has been decreased by a process, it cannot be
(unless a process has SYSOPS privilege), even back to the
original system limit.
Set the file size limit to 51,200 bytes:
ulimit -f 100
X/Open Portability Guide, Version 4.
``Large File Support''.
Considerations for large file support
(larger than 2GB)
are supported in this release.
However, file size limits are only discretely settable up to
2GB (more precisely, 2GB -1 byte).
Setting a file size limit greater than or equal to 2GB -1
has the equivalent effect to setting the file size limit to
unlimited is currently defined as
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004