GETCONF(1) FreeBSD General Commands Manual GETCONF(1)


getconfretrieve standard configuration variables


getconf [ -v environment] path_var file

getconf [ -v environment] system_var


The getconf utility prints the value of a POSIX or X/Open path or system configuration variable to the standard output. If the specified variable is undefined, the string “ undefined” is output.

The first form of the command, with two mandatory arguments, retrieves file- and file system-specific configuration variables using pathconf(2). The second form, with a single argument, retrieves system configuration variables using confstr(3) and sysconf(3), depending on the type of variable. As an extension, the second form can also be used to query static limits from < limits.h>.

All sysconf(3) and pathconf(2) variables use the same name as the manifest constants defined in the relevant standard C-language bindings, including any leading underscore or prefix. That is to say, system_var might be ARG_MAX or _POSIX_VERSION, as opposed to the sysconf(3) names _SC_ARG_MAX or _SC_POSIX_VERSION. Variables retrieved from confstr(3) have the leading ‘ _CS_’ stripped off; thus, _CS_PATH is queried by a system_var of “ PATH”.

Programming Environments

The -v environment option specifies a IEEE Std 1003.1-2001 (“POSIX.1”) programming environment under which the values are to be queried. This option currently does nothing, but may in the future be used to select between 32-bit and 64-bit execution environments on platforms which support both. Specifying an environment which is not supported on the current execution platform gives undefined results.

The standard programming environments are as follows:

Exactly 32-bit integer, long, pointer, and file offset. Supported platforms: None.
Exactly 32-bit integer, long, and pointer; at least 64-bit file offset. Supported platforms: IA32, PowerPC.
Exactly 32-bit integer; exactly 64-bit long, pointer, and file offset. Supported platforms: Alpha, SPARC64.
At least 32-bit integer; at least 64-bit long, pointer, and file offset. Supported platforms: None.

The command:


returns a newline-separated list of environments in which the width of certain fundamental types is no greater than the width of the native C type long. At present, all programming environments supported by FreeBSD have this property. Several of the confstr(3) variables provide information on the necessary compiler and linker flags to use the standard programming environments described above.


The getconf utility exits 0 on success, and >0 if an error occurs.


The command:

getconf PATH

will display the system default setting for the PATH environment variable.

The command:

getconf NAME_MAX /tmp

will display the maximum length of a filename in the /tmp directory.

The command:


will display the maximum value of the C type long in the POSIX_V6_LPBIG_OFFBIG programming environment, if the system supports that environment.


Use of a system_var or path_var which is completely unrecognized is considered an error, causing a diagnostic message to be written to standard error. One which is known but merely undefined does not result in an error indication. The getconf utility recognizes all of the variables defined for IEEE Std 1003.1-2001 (“POSIX.1”), including those which are not currently implemented.


The getconf utility is expected to be compliant with IEEE Std 1003.1-2001 (“POSIX.1”).


The getconf utility first appeared in FreeBSD 5.0.


Garrett A. Wollman <wollman@lcs.mit.edu>
September 18, 2002 FreeBSD