The tool nb first searches its indexes for file:line references¹
with all the given keywords (without any keyword starting with -).
It then indexes lines starting with nb or #nb in files in the
current directory (nbindex), and adds the current directory to
a list of known indexes (nbindexes).²
 ¹ The index contains lines of the form file:line which can be
directly clicked on in Acme to bring up the file and highlight
the line.
 ² Add an absolute path to nbindexes.  As provided, nbindexes
is stored in the current directory, which does not let you search
indexes across directories.

The filter nbdoc expands file:line references, in nb output,
to the full text of the indexed note.

The filter so counts keywords in nb output, and orders them
by frequency.

The tool kanban lists index lines which match a set of
specific _keywords, modelled after a kanban process.

Since inferno will only find and run scripts from the current
directory or /dis, the tool redirect takes the name of a script in
another directory structure, and searches for and runs that script.

Check the rc directory for versions of these scripts that will run in
the rc shell (Plan 9, plan9port, Byron Ratiktzis's rewrite for *nix).

This project also includes an extensive example:
my public notebook, in directory catenate.