unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (SunOS-5.10)
Page:
Section:
Apropos / Subsearch:
optional field

limit(1)                         User Commands                        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]

DESCRIPTION
   /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 limits.

       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. (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).

       -h       Use  hard  limits  instead  of the current limits. Hard limits
                impose a ceiling on the values of the current limits. Only the
                privileged 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 sysdef()).



       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 speci-
       fied. 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 pro-
                cesses (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  tun-
       ables.  The  only  controls  for  these are hard limits, set in a shell
       startup file, or system-wide soft limits, which, for the  current  ver-
       sion of the Solaris OS, is 2**64bytes.

OPTIONS
       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.



OPERANDS
       The following operand is supported by ulimit:

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



EXAMPLES
   /usr/bin/ulimit
       Example 1: Limiting the stack size

       To limit 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

       To limit 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

       To limit 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

       To remove 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

ENVIRONMENT VARIABLES
       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.

EXIT STATUS
       The following exit values are returned by ulimit:

       0        Successful completion.



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



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


       tab()    allbox;    cw(2.750000i)|     cw(2.750000i)     lw(2.750000i)|
       lw(2.750000i).    ATTRIBUTE   TYPEATTRIBUTE  VALUE  AvailabilitySUNWcsu
       Interface StabilityStandard


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




SunOS 5.10                        8 Apr 2004                          limit(1)