sysconf -- a sysctl(8)-like utility for managing /etc/rc.conf et. al.

[Garrett Cooper]

On Wed, Oct 6, 2010 at 1:45 PM, Devin Teske <dteske at vicor.com> wrote:
> Hello fellow freebsd-hackers,
>
> Long-time hacker, first-time poster.
>
> I'd like to share a shell script that I wrote for FreeBSD system
> administration.
>
> The attached shell script works similar to sysctl(8), but rather than
> querying or working on sysctl MIBs, it instead works on the /etc/rc.conf
> (and /etc/rc.conf.local) files.
>
> Syntax shown below (available by running the script without arguments):
>
> Usage: sysconf [OPTIONS] name[=value] ...
> OPTIONS:
>        -h --help   Print this message to stderr and exit.
>        -d          Print list of internal dependencies before exit.
>        -e          Print query results as `var=value' (useful for producing
>                    output to be fed back in). Ignored if -n is specified.
>        -n          Show only variable values, not their names.
>
> ENVIRONMENT:
>        SYSCONF_SHOW_DEPS     Dump list of dependencies. Must be zero or one
>                              (default: `0')
>        RC_DEFAULTS           Location of `/etc/defaults/rc.conf' file.
>
> Examples:
>
> root at mymachine ~ $ sysconf hostname
> hostname: mymachine.localdomain
> root at mymachine ~ $ sysconf hostname=foomaster.deluxe.com
> hostname: mymachine.localdomain -> foomaster.deluex.com
> root at mymachine ~ $ sysconf -e hostname
> hostname="foomaster.deluxe.com"
> root at mymachine ~ $ sysconf -n hostname
> foomaster.deluxe.com
>
> The script has zero external dependencies. None. Period. It will use
> grep(1) if installed, but it is not required.
>
> Tested extensively on FreeBSD-4.8, FreeBSD-4.11, FreeBSD-8.0, and
> FreeBSD-8.1.

    I haven't looked at this yet, but this will result in user
confusion as it differs in purpose from sysconf(3) (which is a POSIX
API that helps determine system configuration tunable variables)...
Thanks,
-Garrett