ulimit(1)ulimit(1)NAMEulimit - Sets or reports a resource limit
SYNOPSISulimit [-HSacdfmnstvw] [limit]
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
ulimit: XCU5.0, XBD5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
[Tru64 UNIX] The limits specified for the resources are hard limits.
A hard limit cannot be increased once it is set. [Tru64 UNIX] The
limits specified for the resources are soft limits. A soft limit can
be increased up to the value of the hard limit. [Tru64 UNIX] Lists
all of the current resource limits. The limit operand is not permitted
with this option. [Tru64 UNIX] The limit operand specifies the num‐
ber of 512-byte blocks for core dumps. [Tru64 UNIX] The limit oper‐
and specifies the number of Kilobytes for the data area. The limit op‐
erand specifies the number of 512-byte blocks for files written by
child processes (files of any size can be read). [Tru64 UNIX] The
limit operand specifies the number of Kilobytes for the size of physi‐
cal memory. [Tru64 UNIX] The limit operand specifies the number of
file descriptors. [Tru64 UNIX] The limit operand specifies the num‐
ber of Kilobytes for the stack area. [Tru64 UNIX] The limit operand
specifies the number of seconds to be used by each process. [Tru64
UNIX] The limit operand specifies the number of Kilobytes for virtual
memory. This option is supported only if RLIMIT_VMEM has been defined
in /usr/include/sys/resource.h at compile-time. [Tru64 UNIX] The
limit operand specifies the number of Kilobytes for the swap area.
This option is supported only if RLIMIT_SWAP has been defined in
/usr/include/sys/resource.h at compile-time.
If no options are specified, this is the number of 512 byte blocks to
use as the new limit to file size. Otherwise, it is the limit applied
to the resource indicatd by the option.
[Tru64 UNIX] This operand is not allowed with the -a option.
If this operand is omitted, the current limit for the indicated
resource is reported.
This command sets, or reports, the limit on the size of system
resources, as indicated by the option.
[Tru64 UNIX] If neither the -H option nor the -S option is specified,
the limit applies to both hard and soft limits. If only the -a option
is specified, soft limits are reported.
If there is no limit on a resource, the limit is reported as unlimited.
The ulimit command affects only the current execution environment,
therefore it has no effect when run in a separate execution environment
such as one of the following:
nohup ulimit-f 10000 env ulimit 10000
Once a limit has been decreased, only a user with superuser privileges
may increase it, even back to its original value.
The following exit values are returned: Successful completion. A
request for a higher limit was rejected or an error occurred.
To set the file size limit to 51,200 bytes, enter: ulimit-f 100 To
report the current file size limit, enter: ulimit The following example
displays all current resource limits: % ulimit-a
time(seconds) unlimited file(blocks) unlimited
data(kbytes) 131072 stack(kbytes) 2048 memory(kbytes)
84280 coredump(blocks) unlimited nofiles(descriptors) 4096 vmem‐
The following environment variables affect the execution of ulimit:
Provides a default value for the internationalization variables that
are unset or null. If LANG is unset or null, the corresponding value
from the default locale is used. If any of the internationalization
variables contain an invalid setting, the utility behaves as if none of
the variables had been defined. If set to a non-empty string value,
overrides the values of all the other internationalization variables.
Determines the locale for the interpretation of sequences of bytes of
text data as characters (for example, single-byte as opposed to multi‐
byte characters in arguments). Determines the locale for the format
and contents of diagnostic messages written to standard error. Deter‐
mines the location of message catalogues for the processing of LC_MES‐