Dan Jacobson <[EMAIL PROTECTED]> writes:
> $ env k-o=4 ...
OK, thanks, I installed this patch to address this and a somewhat-related
issue (special built-in utilities).
2004-10-11 Paul Eggert <[EMAIL PROTECTED]>
* coreutils.texi (Special built-in utilities): New node.
(printf invocation): builtin -> built-in, for consistency
with POSIX terminology.
(test invocation, pwd invocation):
Use specific rather than generic language to warn about
built-in commands.
(chroot invocation, env invocation, nice invocation, nohup invocation):
Warn that command must not be a special built-in.
(env invocation): Warn about environment variables with unusual
spellings, or duplicates.
Index: coreutils.texi
===================================================================
RCS file: /fetish/cu/doc/coreutils.texi,v
retrieving revision 1.216
retrieving revision 1.218
diff -p -u -r1.216 -r1.218
--- coreutils.texi 26 Sep 2004 22:56:04 -0000 1.216
+++ coreutils.texi 11 Oct 2004 23:47:20 -0000 1.218
@@ -649,6 +649,7 @@ name.
* Trailing slashes:: --strip-trailing-slashes, in some programs.
* Traversing symlinks:: -H, -L, or -P, in some programs.
* Treating / specially:: --preserve-root and --no-preserve-root.
+* Special built-in utilities:: @command{break}, @command{:}, @command{eval}, @dots{}
* Standards conformance:: Conformance to the @acronym{POSIX} standard.
@end menu
@@ -1126,6 +1127,34 @@ when operating recursively on @file{/},
more quickly, and hence damage more files before an alert user can
interrupt them.
[EMAIL PROTECTED] Special built-in utilities
[EMAIL PROTECTED] Special built-in utilities
+
+Some programs like @command{nice} can invoke other programs; for
+example, the command @samp{nice cat file} invokes the program
[EMAIL PROTECTED] by executing the command @samp{cat file}. However,
[EMAIL PROTECTED] built-in utilities} like @command{exit} cannot be invoked
+this way. For example, the command @samp{nice exit} does not have a
+well-defined behavior: it may generate an error message instead of
+exiting.
+
+Here is a list of the special built-in utilities that are standardized
+by @acronym{POSIX} 1003.1-2004.
+
[EMAIL PROTECTED]
[EMAIL PROTECTED]@: : break continue eval exec exit export readonly
+return set shift times trap unset}
[EMAIL PROTECTED] quotation
+
+For example, because @samp{.}, @samp{:}, and @samp{exec} are special,
+the commands @samp{nice . foo.sh}, @samp{nice :}, and @samp{nice exec
+pwd} do not work as you might expect.
+
+Many shells extend this list. For example, Bash has several extra
+special built-in utilities like @command{history}, and
[EMAIL PROTECTED], and with Bash the command @samp{nice suspend}
+generates an error message instead of suspending.
+
@node Standards conformance
@section Standards conformance
@@ -9277,7 +9306,7 @@ $ /usr/local/bin/printf '\u4e2d\u6587'
will be output correctly in all Chinese locales (GB2312, BIG5, UTF-8, etc).
Note that in these examples, the full name of @command{printf} has been
-given, to distinguish it from the GNU @code{bash} builtin function
+given, to distinguish it from the GNU @code{bash} built-in function
@command{printf}.
For larger strings, you don't need to look up the hexadecimal code
@@ -9430,8 +9459,8 @@ test
@cindex conflicts with shell built-ins
@cindex built-in shell commands, conflicts with
-Because most shells have a built-in command by the same name, using the
-unadorned command name in a script or interactively may get you
+Because most shells have a built-in @command{test} command, using an
+unadorned @command{test} in a script or interactively may get you
different functionality than that described here.
If @var{expression} is omitted, @command{test} returns false.
@@ -10200,8 +10229,8 @@ names---none will be symbolic links.
@cindex conflicts with shell built-ins
@cindex built-in shell commands, conflicts with
-Because most shells have a built-in command by the same name, using the
-unadorned command name in a script or interactively may get you
+Because most shells have a built-in @command{pwd} command, using an
+unadorned @command{pwd} in a script or interactively may get you
different functionality than that described here.
The only options are a lone @option{--help} or
@@ -12016,6 +12045,8 @@ the directory @var{newroot} (which must
@var{command} with optional @var{args}. If @var{command} is not
specified, the default is the value of the @env{SHELL} environment
variable or @command{/bin/sh} if not set, invoked with the @option{-i} option.
[EMAIL PROTECTED] must not be a special built-in utility
+(@pxref{Special built-in utilities}).
The only options are @option{--help} and @option{--version}. @xref{Common
options}. Options must precede operands.
@@ -12075,21 +12106,33 @@ env [EMAIL PROTECTED]@dots{} [EMAIL PROTECTED]@v
env
@end example
-Arguments of the form @[EMAIL PROTECTED]@var{value}} set
+Operands of the form @[EMAIL PROTECTED]@var{value}} set
the environment variable @var{variable} to value @var{value}.
@var{value} may be empty (@[EMAIL PROTECTED]). Setting a variable
to an empty value is different from unsetting it.
+These operands are evaluated left-to-right, so if two operands
+mention the same variable the earlier is ignored.
+
+Environment variable names can be empty, and can contain any
+characters other than @samp{=} and the null character (@acronym{ASCII}
[EMAIL PROTECTED]). However, it is wise to limit yourself to names that
+consist solely of underscores, digits, and @acronym{ASCII} letters,
+and that begin with a non-digit, as applications like the shell do not
+work well with other names.
@vindex PATH
-The first remaining argument specifies the program name to invoke; it is
+The first operand that does not contain the character @samp{=}
+specifies the program to invoke; it is
searched for according to the @env{PATH} environment variable. Any
remaining arguments are passed as arguments to that program.
+The program should not be a special built-in utility
+(@pxref{Special built-in utilities}).
@cindex environment, printing
If no command name is specified following the environment
specifications, the resulting environment is printed. This is like
-specifying a command name of @command{printenv}.
+specifying the @command{printenv} program.
The program accepts the following options. Also see @ref{Common options}.
Options must precede operands.
@@ -12155,10 +12198,13 @@ enforce more restrictive limits. An att
outside the supported range is treated as an attempt to use the
minimum or maximum supported value.
[EMAIL PROTECTED] must not be a special built-in utility (@pxref{Special
+built-in utilities}).
+
@cindex conflicts with shell built-ins
@cindex built-in shell commands, conflicts with
-Because many shells have a built-in command by the same name, using the
-unadorned command name in a script or interactively may get you
+Because many shells have a built-in @command{nice} command, using an
+unadorned @command{nice} in a script or interactively may get you
different functionality than that described here.
The program accepts the following option. Also see @ref{Common options}.
@@ -12280,6 +12326,9 @@ with an @samp{&}. Also, @command{nohup}
scheduling priority of @var{command}; use @command{nice} for that,
e.g., @samp{nohup nice @var{command}}.
[EMAIL PROTECTED] must not be a special built-in utility (@pxref{Special
+built-in utilities}).
+
The only options are @option{--help} and @option{--version}. @xref{Common
options}. Options must precede operands.
_______________________________________________
Bug-coreutils mailing list
[EMAIL PROTECTED]
http://lists.gnu.org/mailman/listinfo/bug-coreutils
