limit(1)                                                                                                                                  limit(1)

NAME

       limit, ulimit, unlimit - set or get limitations on the system resources available to the current shell and its descendents

SYNOPSIS

       /usr/bin/ulimit [-f] [blocks]

   sh
       ulimit [ - [HS] [ a | cdfnstv]]

       ulimit [ - [HS] [ c | d | f | n | s | t | v]] limit

   csh
       limit [-h] [ resource [limit]]

       unlimit [-h] [resource]

   ksh
       ulimit [-HSacdfnstv] [limit]

   /usr/bin/ulimit
       The  ulimit utility sets or reports the file-size writing limit imposed on files written by the shell and its child processes (files of any
       size may be read). Only a process with appropriate privileges can increase the limit.

   sh
       The Bourne shell built-in function, ulimit, prints or sets hard or soft resource limits. These limits are described in getrlimit(2).

       If limit is not present, ulimit prints the specified limits. Any number of limits may be printed at one time. The -a option prints all lim-
       its.

       If limit is present, ulimit sets the specified limit to limit. The string unlimited requests the largest valid limit. Limits may be set for
       only one resource at a time. Any user may set a soft limit to any value below the hard limit. Any user may  lower  a  hard  limit.  Only  a
       super-user may raise a hard limit. See su(1M).

       The -H option specifies a hard limit. The -S option specifies a soft limit. If neither option is specified, ulimit will set both limits and
       print the soft limit.

       The following options specify the resource whose limits are to be printed or set. If no option is specified, the file size limit is printed
       or set.

       -c       maximum core file size (in 512-byte blocks)

       -d       maximum size of data segment or heap (in kbytes)

       -f       maximum file size (in 512-byte blocks)

       -n       maximum file descriptor plus 1

       -s       maximum size of stack segment (in kbytes)

       -t       maximum CPU time (in seconds)

       -v       maximum size of virtual memory (in kbytes)

   csh
       The  C-shell  built-in function, limit, limits the consumption by the current process or any process it spawns, each not to exceed limit on
       the specified resource. If limit is omitted, print the current limit; if resource is omitted, display all limits.

       -h       Use hard limits instead of the current limits. Hard limits impose a ceiling on the values of the current limits. Only  the  privi-
                leged user may raise the hard limits.

       resource is one of:

       cputime         Maximum CPU seconds per process.

       filesize        Largest single file allowed. Limited to the size of the filesystem (see df(1M)).

       datasize        The maximum size of a process's heap in kilobytes.

       stacksize       Maximum stack size for the process. The default stack size is 2**64.

       coredumpsize    Maximum size of a core dump (file). This is limited to the size of the filesystem.

       descriptors     Maximum  number of file descriptors. Run the sysdef(1M) command to obtain the maximum possible limits for your system.  The
                       values reported are in hexadecimal, but can be translated into decimal numbers using the bc(1) command.

       memorysize      Maximum size of virtual memory.

       limit is a number, with an optional scaling factor, as follows:

       nh              Hours (for cputime).

       nk              n kilobytes. This is the default for all but cputime.

       nm              n megabytes or minutes (for cputime).

       mm:ss           Minutes and seconds (for cputime).

       unlimit removes a limitation on resource. If no resource is specified, then all resource limitations are removed. See  the  description  of
       the limit command for the list of resource names.

       -h              Remove corresponding hard limits. Only the privileged user may do this.

   ksh
       The Korn shell built-in function, ulimit, sets or displays  a resource limit. The available resources limits are listed below. Many systems
       do not contain one or more of these limits. 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 flags specify whether the hard limit or the
       soft limit 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 or -S options is specified, the limit applies to both. The current resource limit is printed when limit
       is omitted. In this case, the soft limit is printed unless -H is specified. When more than one resource is specified, then the  limit  name
       and unit is printed before the 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 area.

       -f       The number of 512-byte blocks on files written by child processes (files of any size may be read).

       -n       The number of file descriptors plus 1.

       -s       The number of K-bytes on the size of the stack area.

       -t       The number of seconds (CPU time) to be used by each process.

       -v       The number of K-bytes for virtual memory.

       If no option is given, -f is assumed.

   Per-Shell Memory Parameters
       The  heapsize,  datasize,  and  stacksize  parameters  are not system tunables. The only controls for these are hard limits, set in a shell
       startup file, or system-wide soft limits, which, for the current version of the Solaris OS, is 2**64bytes.

       The following option is supported by ulimit:

       -f       Sets (or reports, if no blocks operand is present), the file size limit in blocks. The -f option is also the default case.

       The following operand is supported by ulimit:

       blocks   The number of 512-byte blocks to use as the new file size limit.

   /usr/bin/ulimit
       Example 1: Limiting the Stack Size

       The following example limits the stack size to 512 kilobytes:

       example% ulimit -s 512
       example% ulimit -a
       time(seconds)         unlimited
       file(blocks)            100
       data(kbytes)            523256
       stack(kbytes)           512
       coredump(blocks)        200
       nofiles(descriptors)    64
       memory(kbytes)          unlimited

   sh/ksh
       Example 2: Limiting the Number of File Descriptors

       The following command limits the number of file descriptors to 12:

       example$ ulimit -n 12
       example$ ulimit -a
       time(seconds)            unlimited
       file(blocks)             41943
       data(kbytes)             523256
       stack(kbytes)            8192
       coredump(blocks)         200
       nofiles(descriptors)     12
       vmemory(kbytes)          unlimited

   csh
       Example 3: Limiting the Core Dump File Size

       The following command limits the size of a core dump file size to 0 kilobytes:

       example% limit coredumpsize 0
       example% limit
       cputime                 unlimited
       filesize                unlimited
       datasize                523256 kbytes
       stacksize               8192 kbytes
       coredumpsize            0 kbytes
       descriptors             64
       memorysize              unlimited

       Example 4: Removing the limitation for core file size

       The following command removes the above limitation for the core file size:

       example% unlimit coredumpsize
       example% limit
       cputime                 unlimited
       filesize                unlimited
       datasize                523256 kbytes
       stacksize               8192 kbytes
       coredumpsize            unlimited
       descriptors             64
       memorysize              unlimited

       See environ(5) for descriptions of the following environment variables that affect the execution of ulimit: LANG, LC_ALL, LC_CTYPE, LC_MES-
       SAGES, and NLSPATH.

       The following exit values are returned by ulimit:

       0        Successful completion.

       >0       A request for a higher limit was rejected or an error occurred.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWcsu                      |
       +-----------------------------+-----------------------------+
       |Interface Stability          |Standard                     |
       +-----------------------------+-----------------------------+

       bc(1), csh(1), ksh(1), sh(1), df(1M), su(1M), swap(1M), sysdef(1M), getrlimit(2), attributes(5), environ(5), standards(5)

                                                                    19 Aug 2005                                                           limit(1)