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authorPaul Eggert <eggert@cs.ucla.edu>2014-09-08 11:40:39 -0700
committerPaul Eggert <eggert@cs.ucla.edu>2014-09-08 20:48:44 -0700
commit943ca00bba40c50ce95a2ff224998175bcb18ed4 (patch)
tree2134b0689c45019960f13445cc8f31d7004a5b48
parent9a1a715a0068ec1cd59711e3511f8c25cd0ba927 (diff)
downloadcoreutils-943ca00bba40c50ce95a2ff224998175bcb18ed4.tar.xz
doc: mention which commands are optional
* doc/coreutils.texi (coreutils invocation, df invocation) (stty invocation, whoami invocation, nproc invocation) (arch invocation, hostname invocation, hostid invocation) (uptime invocation, chroot invocation, nice invocation) (stdbuf invocation): Document that the command is installed optionally.
-rw-r--r--doc/coreutils.texi49
1 files changed, 49 insertions, 0 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 0178f60c4..14ee3b0ba 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -1516,6 +1516,9 @@ or by explicitly calling @command{coreutils} with the
coreutils @option{--coreutils-prog=PROGRAM} @dots{}
@end example
+The @command{coreutils} command is not installed by default, so
+portable scripts should not rely on its existence.
+
@node Output of entire files
@chapter Output of entire files
@@ -11434,6 +11437,9 @@ Ignored; for compatibility with System V versions of @command{df}.
@end table
+@command{df} is installed only on systems that have usable mount tables,
+so portable scripts should not rely on its existence.
+
@exitstatus
Failure includes the case where no output is generated, so you can
inspect the exit status of a command like @samp{df -t ext3 -t reiserfs
@@ -13841,6 +13847,10 @@ systems, those or other settings also may not
be available, but it's not feasible to document all the variations: just
try it and see.
+@command{stty} is installed only on platforms with the POSIX terminal
+interface, so portable scripts should not rely on its existence on
+non-POSIX platforms.
+
@exitstatus
@menu
@@ -14760,6 +14770,10 @@ that file instead. A common choice is @file{/var/log/wtmp}.
The only options are @option{--help} and @option{--version}. @xref{Common
options}.
+The @command{users} command is installed only on platforms with the
+POSIX @code{<utmpx.h>} include file or equivalent, so portable scripts
+should not rely on its existence on non-POSIX platforms.
+
@exitstatus
@@ -14908,6 +14922,10 @@ After each login name print a character indicating the user's message status:
@end table
+The @command{who} command is installed only on platforms with the
+POSIX @code{<utmpx.h>} include file or equivalent, so portable scripts
+should not rely on its existence on non-POSIX platforms.
+
@exitstatus
@@ -15641,6 +15659,9 @@ arch [@var{option}]
The program accepts the @ref{Common options} only.
+@command{arch} is not installed by default, so portable scripts should
+not rely on its existence.
+
@exitstatus
@@ -15832,6 +15853,10 @@ hostname [@var{name}]
The only options are @option{--help} and @option{--version}. @xref{Common
options}.
+@command{hostname} is not installed by default, and other packages
+also supply a @command{hostname} command, so portable scripts should
+not rely on its existence or on the exact behavior documented above.
+
@exitstatus
@@ -15857,6 +15882,10 @@ On that system, the 32-bit quantity happens to be closely
related to the system's Internet address, but that isn't always
the case.
+@command{hostid} is installed only on systems that have the
+@code{gethostid} function, so portable scripts should not rely on its
+existence.
+
@exitstatus
@node uptime invocation
@@ -15890,6 +15919,13 @@ also include processes in the uninterruptible sleep state (that is,
those processes which are waiting for disk I/O). The Linux kernel
includes uninterruptible processes.
+@command{uptime} is installed only on platforms with infrastructure
+for obtaining the boot time, and other packages also supply an
+@command{uptime} command, so portable scripts should not rely on its
+existence or on the exact behavior documented above.
+
+@exitstatus
+
@node SELinux context
@chapter SELinux context
@@ -16203,6 +16239,10 @@ files to the required positions under your intended new root directory.
Finally, if the executable requires any other files (e.g., data, state,
device files), copy them into place, too.
+@command{chroot} is installed only on systems that have the
+@code{chroot} function, so portable scripts should not rely on its
+existence.
+
@cindex exit status of @command{chroot}
Exit status:
@@ -16431,6 +16471,10 @@ option syntax @option{-@var{adjustment}}. New scripts should use
@end table
+@command{nice} is installed only on systems that have the POSIX
+@code{setpriority} function, so portable scripts should not rely on
+its existence on non-POSIX platforms.
+
@cindex exit status of @command{nice}
Exit status:
@@ -16642,6 +16686,11 @@ Specify the size of the buffer to use in fully buffered mode.
@end table
+@command{stdbuf} is installed only on platforms that use the
+Executable and Linkable Format (ELF) and support the
+@code{constructor} attribute, so portable scripts should not rely on
+its existence.
+
@cindex exit status of @command{stdbuf}
Exit status: