Merge and Sync with 4.4BSD-Lite2
Mostly looks like the previous NetBSD version, actually -- only minimal
Lite2 stigmata preserved although I started with Lite2. Mostly the changes
were things like index->strchr and the rest was NetBSD code.

Add RCS indentifiers.

Make Posix 1003.2 (Draft 11.2) compliant.

branches: 1.1.1;
Initial revision

PR bin/59058 Random minor corrections

Use the correct exit status values (126 vs 127), the latter
when the utility cannot be located (no matter why) and the
former when it could be located, but an execvp() attempt
failed for some other reason.

Use exit status 125 for all errors detected by env itself,
which require that it exit, but no longer consider including
the -0 option along with a utility name to be such an error.
The -0 is useless in such a case, but just ignore it (just
as also happens if -u options are given with -i, which makes
all -u options meaningless). Using 125 rather than a low
number (like 1, which it mostly used to be) should make it
slightly easier to detect cases where env has failed, rather
than the named utility having failed.

Write errors to stdout, and failure of putenv() are now
detected and cause an error message and exit(125).

The -C option now (also) causes PWD to be removed from the
environment (better than it retaining an invalid value).
(Currently OLDPWD is left alone, better might be possible.)

Document all of that (and make it much clearer than when a
utility is successfully invoked, the exit status, any value
at all, comes from the utility, rather than pretending that
utilities were only permitted to exit with status from 0..125.

More wording fixes and clarifications in the man page.

While there, delete the BUGS section, after implementing,
and documenting, a mechanism to allow utility names to
contain an '=' character (as useless as this change is
likely to be in practice) - the implemented mechanism is
extraordinarily simple (much simpler than this paragraph!)

Implement "env -C dir" to chdir

Use err(3) to expose errno(2) if chdir(2) (or unsetenv(3)) fails.

branches: 1.15.8; 1.15.10;
Fix a typo (extra `s')

Implement env(1) -0

-0 End each output line with NUL, not newline.

FreeBSD and GNU env(1) implement -0 which is used in 3rd party scripts.

This change is based on the FreeBSD code.

Implement env(1) -u

The option '-u name' causes removal of the name environment variable if
it is in the environment. This is similar to the unset command in sh(1).
The value for name must not include the '=' character.

Add HISTORY section in the man page.

The -u argument is implemented by Linux, FreeBSD and Darwin.
The lack of -u in NetBSD is a cause for a frequent fallout in the LLVM
toolchain test-suite.

branches: 1.12.76;
Improve description of EXIT CODES. Based on the following OpenBSD commit,
forwarded by jmc@openbsd:

rewrite DIAGNOSTICS to avoid confusion about which application returns
what, and when;

started by Jeffrey 'jf' Lim, with some correction from Ingo Schwarze;
ok otto

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22365, verified by myself.

New sentence, new line.

Punctuation nit.

Whitespace cleanup.

For commands and utilities, use EXIT STATUS rather than RETURN VALUES or
DIAGNOSTICS as appropriate (and documented in mdoc(7)).

WARNSify, fix .Nm usage

RCS ID police

branches: 1.4.4;
Fix spelling errors.

Document the fact that env is POSIX.2 compliant.
Change "command" to "utility", as env can only execute stand-alone utilitys
as apposed to built-in commands.

Add RCS indentifiers.

Make Posix 1003.2 (Draft 11.2) compliant.

PR bin/59058 Random minor corrections

Use the correct exit status values (126 vs 127), the latter
when the utility cannot be located (no matter why) and the
former when it could be located, but an execvp() attempt
failed for some other reason.

Use exit status 125 for all errors detected by env itself,
which require that it exit, but no longer consider including
the -0 option along with a utility name to be such an error.
The -0 is useless in such a case, but just ignore it (just
as also happens if -u options are given with -i, which makes
all -u options meaningless). Using 125 rather than a low
number (like 1, which it mostly used to be) should make it
slightly easier to detect cases where env has failed, rather
than the named utility having failed.

Write errors to stdout, and failure of putenv() are now
detected and cause an error message and exit(125).

The -C option now (also) causes PWD to be removed from the
environment (better than it retaining an invalid value).
(Currently OLDPWD is left alone, better might be possible.)

Document all of that (and make it much clearer than when a
utility is successfully invoked, the exit status, any value
at all, comes from the utility, rather than pretending that
utilities were only permitted to exit with status from 0..125.

More wording fixes and clarifications in the man page.

While there, delete the BUGS section, after implementing,
and documenting, a mechanism to allow utility names to
contain an '=' character (as useless as this change is
likely to be in practice) - the implemented mechanism is
extraordinarily simple (much simpler than this paragraph!)

Implement "env -C dir" to chdir

Use err(3) to expose errno(2) if chdir(2) (or unsetenv(3)) fails.

branches: 1.23.8; 1.23.10;
Implement env(1) -0

-0 End each output line with NUL, not newline.

FreeBSD and GNU env(1) implement -0 which is used in 3rd party scripts.

This change is based on the FreeBSD code.

Add CVS Id tag and switch __attribute__ to __dead.

Implement env(1) -u

The option '-u name' causes removal of the name environment variable if
it is in the environment. This is similar to the unset command in sh(1).
The value for name must not include the '=' character.

Add HISTORY section in the man page.

The -u argument is implemented by Linux, FreeBSD and Darwin.
The lack of -u in NetBSD is a cause for a frequent fallout in the LLVM
toolchain test-suite.

branches: 1.20.46;
minor KNF nits.

Do use putenv(3) to handle the provided strings directly, instead of
setenv(3) which need string splitting and later reassembly.

remove duplicate 'was' in a comment

Remove the \n and tabs from the __COPYRIGHT() strings.
Tweak to use a consistent format.

branches: 1.16.22;
de-__P, add ANSI prototypes, and a teeny bit of KNF.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22365, verified by myself.

fix nested extern

Don't declare 'extern opt*' getopt variables.

revert previous

remove superfluous '-' in getopt string

branches: 1.10.6;
WARNSify, fix .Nm usage

Include appropriate header files to bring prototypes into scope.
Removed explicit errno declarations.

Merge and Sync with 4.4BSD-Lite2
Mostly looks like the previous NetBSD version, actually -- only minimal
Lite2 stigmata preserved although I started with Lite2. Mostly the changes
were things like index->strchr and the rest was NetBSD code.

Provide prototypes in static function declarations.

POSIX.2 utilities must call setlocale(LC_ALL, "");

simplify error message handling by using err() function.

Minor tweaks: including header files to bring prototypes into scope,
explicitly declaring function return values, etc. to make gcc -Wall
shut up.

Add RCS identifiers.

Make Posix 1003.2 (Draft 11.2) compliant.

branches: 1.1.1;
Initial revision