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authorJim Meyering <jim@meyering.net>2001-04-20 17:33:43 +0000
committerJim Meyering <jim@meyering.net>2001-04-20 17:33:43 +0000
commit45c63978485ec400640aacc782dd9d3c6171d3be (patch)
tree0d017d0fbec6639e2d60357e17e0e1ca458ca6cd /doc
parent50d41186a429feeefcd6f003a20e3b29a1b82f29 (diff)
downloadcoreutils-45c63978485ec400640aacc782dd9d3c6171d3be.tar.xz
(false invocation): Describe how --help and
--version are treated with and without POSIXLY_CORRECT. (true invocation): Likewise.
Diffstat (limited to 'doc')
-rw-r--r--doc/sh-utils.texi21
1 files changed, 13 insertions, 8 deletions
diff --git a/doc/sh-utils.texi b/doc/sh-utils.texi
index 4670b30d4..08d528aca 100644
--- a/doc/sh-utils.texi
+++ b/doc/sh-utils.texi
@@ -427,9 +427,10 @@ pipeline.
@dfn{failure}. It can be used as a place holder in shell scripts
where an unsuccessful command is needed.
-@code{false} ignores @emph{all} command line arguments, even @samp{--help}
-and @samp{--version}, since to do otherwise would change expected
-behavior that some programmers may be relying on.
+By default, @code{false} honors the @samp{--help} and @samp{--version}
+options. However, that is contrary to @sc{POSIX}, so when the environment
+variable @env{POSIXLY_CORRECT} is set, @code{false} ignores @emph{all}
+command line arguments, including @samp{--help} and @samp{--version}.
This version of @code{false} is implemented as a C program, and is thus
more secure and faster than a shell script implementation, and may safely
@@ -448,11 +449,15 @@ be used as a dummy shell for the purpose of disabling accounts.
@code{true} does nothing except return an exit status of 0, meaning
@dfn{success}. It can be used as a place holder in shell scripts
where a successful command is needed, although the shell built-in
-command @code{:} (colon) does the same thing faster.
-
-@code{true} ignores @emph{all} command line arguments, even @samp{--help}
-and @samp{--version}, since to do otherwise would change expected
-behavior that some programmers may be relying on.
+command @code{:} (colon) may do the same thing faster.
+In most modern shells, @code{true} is built-in command, so when
+you use @samp{true} in a script, you're probably using the built-in
+command, not the one documented here.
+
+By default, @code{true} honors the @samp{--help} and @samp{--version}
+options. However, that is contrary to @sc{POSIX}, so when the environment
+variable @env{POSIXLY_CORRECT} is set, @code{true} ignores @emph{all}
+command line arguments, including @samp{--help} and @samp{--version}.
This version of @code{true} is implemented as a C program, and is thus
more secure and faster than a shell script implementation, and may safely