.TH REVPATH 1 "imake 1.0.10" "X Version 11"
.SH NAME
revpath \- generate a relative path that can be used to undo a change-directory
.SH SYNOPSIS
.B revpath
.I path
.SH DESCRIPTION
The
.I revpath
program prints out a relative path that is the ``reverse'' or ``inverse'' of
.IR path .
Start with two directories
.I top
and
.IR bottom ,
with the latter below the former, and
.I path
is the location of
.I bottom
relative to
.IR top .
The output of
.I revpath
is the location of
.I top
relative to
.IR bottom .
The resulting path contains a trailing `/' character when the result is
non-trivial.
If
.I path
is equivalent to `.', the resulting output is empty.
If
.I path
is invalid in some way (e.g., doesn't represent the path to a subdirectory)
the output is also empty and no error messages are ever generated.
.SH DIAGNOSTICS
There are no diagnostics.  Error conditions are silently ignored, and the
exit status is always 0.
.SH BUGS
It isn't possible to reverse arbitrary relative paths.
If any path element between the two end points of
.I path
is a symbolic link, the results will probably be incorrect.