getconf - get configuration values
getconf system_var
getconf path_var pathname
getconf -a
The getconf(1) utility writes to standard output the
value of system_var or the value of path_var based on
the path name provided as pathname.
The operands supported for system_var and path_var
can be found in POSIX.1 and POSIX.2.
If the operand is valid, but the variable is undefined for the
system, getconf writes the string undefined to standard
output.
This implementation of getconf supports an option (an
extension from the standard):
- -a
- List the known system variables. Names that require a path name
are given the path name ".".
The following system variables are supported for
system_var:
- _SC_2_C_BIND
- Whether system provides POSIX.2 C language bindings.
- _SC_2_C_DEV
- Whether system supports the POSIX.2 C-Language Development
Utilities Option.
- _SC_2_CHAR_TERM
- Whether system supports at least one terminal type capable of
supporting all operations described in POSIX.2.
- _SC_2_FORT_RUN
- Whether system supports POSIX.2 FORTRAN Runtime Utilities
Option.
- _SC_2_FORT_DEV
- Whether system supports POSIX.2 FORTRAN Development Utilities
Option.
- _SC_2_LOCALEDEF
- Whether system supports the creation of locales.
- _SC_2_SW_DEV
- Whether system supports POSIX.2 Software Development
Portability Utilities Option.
- _SC_2_UPE
- Whether system supports POSIX.2 User Portability Utilities
Option
- _SC_2_VERSION
- Version of ISO/IEC 9945 (POSIX 1003.2) with which the system
attempts to comply.
- _SC_ARG_MAX
- Maximum bytes of argument to exec(3).
- _SC_BC_BASE_MAX
- Maximum obase value allowed by bc(1).
- _SC_BC_DIM_MAX
- Maximum number of elements in a array.
- _SC_BC_SCALE_MAX
- Maximum scale value allowed by bc(1).
- _SC_BC_STRING_MAX
- Maximum length of a string constant in bc(1).
- _SC_CHILD_MAX
- Maximum number of simultaneous processes per user identifier
(ID).
- _SC_CLK_TCK
- Number of micro-seconds per hz tick.
- _SC_COLL_WEIGHTS_MAX
- In a locale definition file, the maximum number of weights that
can be assigned to the LC_COLLATE order keyword.
- _SC_EXPR_NEST_MAX
- Maximum number of expressions that can be nested within
parentheses by expr(1).
- _SC_JOB_CONTROL
- Return 1 if job control is available on this system; otherwise,
returns -1.
- _SC_LINE_MAX
- Maximum length in bytes, including trailing newline, of an
input line for a text-processing utility
- _SC_NGROUPS_MAX
- Maximum number of supplemental groups.
- _SC_OPEN_MAX
- Maximum number of open files per user ID.
- _SC_PAGE_SIZE
- The virtual memory page size. This is always 65536 (64 KB),
regardless of the actual Windows page size.
- _SC_PAGESIZE
- The virtual-memory page size. This is always 65536 (64 KB),
regardless of the actual Windows page size.
- _SC_RE_DUP_MAX
- Maximum number of repetitions of a basic regular expression
allowed in \{m,n\}
notation.
- _SC_SAVED_IDS
- Returns 1 if saved set-group and saved set-user ID is
available; otherwise, returns -1.
- _SC_STREAM_MAX
- Minimum maximum number of streams that a process can have open
at any one time.
- _SC_TZNAME_MAX
- Minimum maximum number of types supported for the name of a
time zone.
- _SC_VERSION
- The version of ISO/IEC 9945 (POSIX 1003.1) with which the
system attempts to comply.
The following path variables are supported for
path_var:
- _PC_LINK_MAX
- The maximum file link count.
- _PC_MAX_CANON
- The maximum number of bytes in terminal canonical input
line.
- _PC_MAX_INPUT
- The minimum maximum number of bytes for which space is
available in a terminal input queue.
- _PC_NAME_MAX
- The maximum number of bytes in a file name.
- _PC_PATH_MAX
- The maximum number of bytes in a path name.
- _PC_PIPE_BUF
- The maximum number of bytes that will be written atomically to
a pipe.
- _PC_CHOWN_RESTRICTED
- Return 1 if appropriate privileges are required for the
chown(3) system call; otherwise, return 0.
- _PC_NO_TRUNC
- Return 1 if file names longer than {KERN_NAME_MAX} are
truncated.
- _PC_VDISABLE
- Returns the terminal character disabling value.
The getconf(1) utility exits with 0 if the operand is
valid, and >0 if an error occurs.
To determine the number of child processes supported on
Interix:
$ getconf CHILD_MAX
28
To determine the minimum number of child processes mandated by
POSIX.1:
$ getconf _POSIX_CHILD_MAX
6
SEE ALSO
pathconf(2)
sysconf(2)