In computing, the
working directory of a
process is the
directory of a hierarchical
file system, if any,
[Operating systems exist that support a hierarchical file system but no concept of "working directory"; an example is Texas Instruments' DX10, used for the TI-990 series.] which is implicitly used to determine the file referenced to by the process with a file name only, or with a relative
path (as opposed to files referenced by full pathnames —see
file name resolution). In most
DOS and
UNIX command shells, as well as in Windows' command line interpreter, the working directory can be changed by using the
cd or
chdir commands. In UNIX, the
pwd command outputs the absolute pathname of the current working directory; the equivalent command in DOS is
cd without
arguments (whereas in Unix,
cd used without arguments takes the user back to his/her
home directory). The
POSIX function
chdir(), where available, can be used to set the invoking process' working directory programmatically.