Q: How do I access the individual 'mounts' database entries using niutil?  Because of the slashes in the property values, niutil doesn't seem to understand the input.

A: Indeed, if you try something straightforward like:

niutil -read . /mounts//dev/sd0a

you get an error message such as

niutil: can't open .:/mounts//dev/rsd0a

because niutil is using / to separate properties.  So, let's say we have the following:

% niutil -list . /mounts
133      /dev/sd0a
134      /dev/sd0b
137      /dev/sd1a

and we want to execute niutil -read on the /dev/sd0a entry.  We have to find some way to escape those slashes in the property value ("/dev/sd0a") or we're sunk.  The simple ways don't work:

% niutil -read . /mounts\/dev\/rsd0a
niutil: can't open .:/mounts/dev/rsd0a

% niutil -read . /mounts/'/dev/rsd0a'
niutil: can't open .:/mounts//dev/rsd0a

Turns out it's necessary to use a DOUBLE backslash to get the proper escaping:

% niutil -read . /mounts/\\/dev\\/sd0a
name: /dev/sd0a
dir: /
type: 4.3
opts: rw noquota noauto
freq: 1
passno: 1

Why?  Because if one types simply '\/' the shell gobbles the escape character
(the \), and transform this into '/'.  If one types TWO slashes, then the shell turns
them into one, and there is one in the string passed to niutil as its argument.

QA344

Valid for 1.0, 2.0,3.0,3.1