fixup: flux-uri manpage

doc/man1/flux-uri.rst

@@ -20,8 +20,9 @@ fully-resolved, native Flux URIs.
 
 Processes running within a Flux instance will have the ``FLUX_URI``
 environment variable set to a native URI which :man3:`flux_open` will
-use by default. Therefore, there is usually no need to specify a URI when
-connecting to the enclosing instance. However, connecting to a _different_
+use by default, with fallback to a compiled-in native URI for the system
+instance of Flux. Therefore, there is usually no need to specify a URI when
+connecting to the enclosing instance. However, connecting to a *different*
 Flux instance will require discovery of the fully-resolved URI for that
 instance.
 
@@ -32,7 +33,8 @@ parts passed to a plugin which implements the resolution method.
 
 As a convenience, if *TARGET* is specified with no scheme, then the scheme
 is assumed to be ``jobid``.  This allows ``flux uri`` to be used to look
-up the URI for a Flux instance running as a job with:
+up the URI for a Flux instance running as a job in the current enclosing
+instance with:
 
 ::
 
@@ -58,10 +60,10 @@ OPTIONS
 =======
 
 **-remote**
-   Return the _remote_ (``ssh://``)  equivalent of the resolved URI.
+   Return the *remote* (``ssh://``)  equivalent of the resolved URI.
 
 **--local**
-   Return the _local_ (``local://``) equivalent of the resulved URI.
+   Return the *local* (``local://``) equivalent of the resulved URI.
    Warning: the resulting URI may be invalid for the current system
    if the network host specified by an ``ssh`` URI is not the current
    host.
@@ -82,8 +84,10 @@ jobid:ID[/ID...]
 pid:PID
   This scheme attempts to read the ``FLUX_URI`` value from the process id
   *PID* using ``/proc/PID/environ``. If *PID* refers to a ``flux-broker``,
-  then a child of the broker is used instead in order to obtain the
-  URI for that broker (instead of its parent)
+  then the scheme reads ``FLUX_URI`` from the broker's initial program or
+  another child process since ``FLUX_URI`` in the broker's environment
+  would refer to *its* parent (or may not be set at all in the case of a
+  test instance started with ``flux start --test-size=N``).
 
 slurm:JOBID
   This scheme makes a best-effort to resolve the URI of a Flux instance
@@ -120,14 +124,13 @@ Get the URI of a nested job:
 .. note::
    With  the ``jobid`` resolver, ``?local`` only needs to be placed on
    the last component of the jobid "path" or hierarchy. This will resolve
-   each URI in turn as a local URI, so it is only useful if all jobs
-   are actually running on the local system.
+   each URI in turn as a local URI.
 
 Get the URI of a local flux-broker
 
 ::
 
-   $ flux uri pid:$(pidof flux-broker | cut -d' ' -f1)
+   $ flux uri pid:$(pidof -s flux-broker)
    local:///tmp/flux-sLuBkZ/local-0
 
 Get the URI for a Flux instance running as a Slurm job: