Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Take a group name on the command-line if available.

Rewrite groupmgmt -- hooking it into the scripting system with dispatch
commands groupAdd, groupDelete, and groupEdit. Getting rid of the awkward-
to-use `groupinput' bolt-on which Ron and I talked about rewriting.

Performance and debugging enhancements:
+ Remove UNAME_P=$(...) from startup/misc -- already supplied by common.subr
+ Use f_getvar instead of $(eval echo \$$var) -- f_getvar is sub-shell free
+ Add `-e' and `-k var' options to f_eval_catch -- increasing use-cases
+ Use f_eval_catch to display errors on failure -- reducing duplicated code
+ Use f_eval_catch when we need output from a command -- improving debugging
+ Optimize f_isinter of strings.subr for performance -- now sub-shell free
+ Improve error checking on pidfiles -- using f_eval_catch and f_isinteger
+ Use $var_to_set arg of f_ifconfig_{inet,netmask} -- eliminate sub-shells
+ Use f_sprintf instead of $(printf ...) -- consolidate sub-shells
+ Use $var_to_set arg of f_route_get_default -- eliminate sub-shells
+ Add f_count to replace $(set -- ...;echo $#) -- eliminate sub-shells
+ Add f_count_ifs to replace $(IFS=x;set -- ...;echo $#) -- no sub-shells
+ Replace var="$var${var:+ }..." in loops with var="$var ..." with a follow-
up var="${var# }" to trim leading whitespace -- optimize loops
+ Use $var_to_set arg of f_resolv_conf_nameservers -- eliminate sub-shells
+ Comments for the f_eval_catch function
+ Remove a duplicate `local ... desc ...' in f_device_get_all of device.subr
+ Use $var_to_set arg of f_device_capacity -- eliminate sub-shells
+ Whitespace fixes in f_dialog_init of dialog.subr
+ Optimize f_inet_atoi of media/tcpip.subr for performance -- sub-shell free
+ In several cases, send stderr to /dev/null -- clean up runtime execution
+ Change f_err of common.subr to go to program stderr not terminal stderr,
allowing redirection of output from functions that use f_err
+ Disable debugging when using f_getvar to get variable argument to
f_startup_rcconf_map_expand of startup/rcconf.subr
+ Use f_replace_all instead of $(echo ... | tr | sed) -- performance
+ Add a $var_to_set option to f_index_{file,menusel_{command,keyword}} of
common.subr -- centralize sub-shells

Introduce centralized [X]dialog(1) exit codes to `dialog.subr' and make-use
throughout the bsdconfig(8) code. While we're here, add an explicit argument
to lvalue-seeking invocations of "return" that previously had no argument.
Also, consolidate a single instance of double-newline and remove some
comments that are no longer required (given increased readability with new
exit codes).

Approved by: re (glebius)

More whitespace.

When the fall-back of a case-statement is the last thing executed in a
while-loop _and_ all prior matches in the same case-statement either break
or continue, we can safely break the fall-back out of the case-statement.
This should improve readability and allow for longer-lines by reducing the
level of indentation by-one for the fall-back case.
(a continuation of SVN r252019)

Remove extra whitespace lines.

Improve portion of the dialog(1) API in dialog.subr responsible for
retrieving stored data (for the --menu, --calendar, --timebox, --checklist,
and --radiolist widgets).

When we (Ron McDowell and I) developed the first version of bsdconfig, it
used temporary files to store responses from dialog(1). That hasn't been
true for some very long time, so the need to always store the return status
of dialog(1) and then call some function to clean-up is long-deprecated. The
function that used to do the clean-up was f_dialog_menutag().

We really don't need f_dialog_menutag() for its originally designed purpose,
as all dialog invocations (even when in a sub-shell) do not use temporary
files anymore.

However, we do need to keep f_dialog_menutag() around because it still fills
the need of being able to abstract the procedure for fetching stored data
provided by functions that display the aforementioned widgets.

In re-designing f_dialog_menutag(), four important changes are made:

1. Rename f_dialog_menutag() to f_dialog_menutag_fetch()
2. Introduce the new first-argument of $var_to_set to reduce number of forks
3. Create a corresponding f_dialog_menutag_store() to abstract the storage
4. Offload the sanitization to a new function, f_dialog_data_sanitize()

NOTE: That last one is important. Not all functions need to store their data
for later fetching, meanwhile every invocation of dialog should be sanitized
(as we learned early-on in the i18n-effort -- underlying libraries will spit
warnings to stderr for bad values of $LANG and since dialog outputs its
responses to stderr, we need to sanitize every response of these warnings).

These changes greatly improve readbaility and also improve performance by
reducing unnecessary forking.

Centralize standard getopts arguments, both for convenience and to correct
a bug in which certain combinations of arguments produced unexpected results
such as `-dX' (now properly produces debugging and X11), `-XS' (now properly
produces X11 in secure mode), `-df-' (enables debugging when reading a
script from standard-input, etc. Multi-word variations such as `-d -X',
`-X -S', `-d -f-', `-d -f -', etc. also work as expected. Also tested were
variations in argument order, which are now working as expected.

UI improvements. First, implement --default-item whenever and wherever
possible to save keystrokes. Second, overhaul startup/rcdelete for much
improved performance. Last, but not least, kill-off useage of --clear
and implement --keep-tite in harmony to minimize jarring transitions.
Also, fix local variable names where necessary while we're here with
other minor comment-enhancements/typo-corrections.

Add new flags `-d' (sets debug=1) and `-D file' (sets debugFile) and
improve debugging initialization. Also fixup USAGE statements while we're
here. Also, change initialization of main program to _not_ change working
directory, allowing the debugFile to be relative without confusion.

Add more debugging to help with diagnosis of program-flow when needed.

Remove unnecessary duplicate initialization of the dialog(1) API (automatically
bootstrapped on-include unless DIALOG_SELF_INITIALIZE is set to NO before-hand)

Improve the debugging abilities and clean up debug messages. In most cases,
all one has to do is set the environment variable DEBUGGING to get the debug
messages to appear on the console.

Replicate a feature from sysinstall documented in
stable/9/usr.sbin/sysinstall/help/shortcuts.hlp (reproduced below):

If /usr/sbin/sysinstall is linked to another filename, say
`/usr/local/bin/configPackages', then the basename will be used
as an implicit command name.

To get a list of modules you can link to, see `bsdconfig -h' output.

Approved by: adrian (co-mentor) (implicit)

Move major includes into /usr/share/bsdconfig for easy external access.

Reviewed by: adrian (co-mentor)
Approved by: adrian (co-mentor)

Import bsdconfig(8) as a replacement for the post-install abilities of
deprecated sysinstall(8). NOTE: WITH_BSDCONFIG is currently required.

Submitted by: Devin Teske (dteske), Ron McDowell <rcm@fuzzwad.org>
Reviewed by: Ron McDowell <rcm@fuzzwad.org>
Approved by: Ed Maste (emaste)