<orderedlist>
<listitem><para>Close all open file
- descriptors except STDIN, STDOUT,
- STDERR (i.e. the first three file
+ descriptors except stdin, stdout,
+ stderr (i.e. the first three file
descriptors 0, 1, 2). This ensures
that no accidentally passed file
descriptor stays around in the daemon
<listitem><para>In the daemon process,
connect <filename>/dev/null</filename>
- to STDIN, STDOUT,
- STDERR.</para></listitem>
+ to standard input, output, and error.
+ </para></listitem>
<listitem><para>In the daemon process,
reset the umask to 0, so that the file
service.</para>
<para>Note that new-style init systems
- guarantee execution of daemon processes in
- a clean process context: it is guaranteed that
+ guarantee execution of daemon processes in a
+ clean process context: it is guaranteed that
the environment block is sanitized, that the
signal handlers and mask is reset and that no
left-over file descriptors are passed. Daemons
- will be executed in their own session, and
- STDIN/STDOUT/STDERR connected to
+ will be executed in their own session, with
+ standard input/output/error connected to
<filename>/dev/null</filename> unless
- otherwise configured. The umask is reset.</para>
+ otherwise configured. The umask is reset.
+ </para>
<para>It is recommended for new-style daemons
to implement the following:</para>
<listitem><para>Instead of using the
<function>syslog()</function> call to log directly to the
system syslog service, a new-style daemon may
- choose to simply log to STDERR via
+ choose to simply log to standard error via
<function>fprintf()</function>, which is then forwarded to
syslog by the init system. If log
priorities are necessary, these can be
#define SD_DEBUG "<7>" /* debug-level messages */</programlisting>
<para>These prefixes are intended to be used in
- conjunction with STDERR-based logging as implemented
+ conjunction with stderr-based logging as implemented
by systemd. If a systemd service definition file is
configured with <varname>StandardError=syslog</varname>
or <varname>StandardError=kmsg</varname>, these
messages written to this file descriptor as simple
newline-separated text strings are written to the
journal. This file descriptor can be used internally
- by applications or be made STDOUT/STDERR of other
- processes executed.</para>
+ by applications or be made standard output or standard
+ error of other processes executed.</para>
<para><function>sd_journal_stream_fd()</function>
takes a short program identifier string as first
<listitem>
<para>Check whether any of the specified units are active
- (i.e. running). Returns an exit code 0 if at least one is
- active, or non-zero otherwise. Unless <option>--quiet</option>
- is specified, this will also print the current unit state to
- STDOUT.</para>
+ (i.e. running). Returns an exit code
+ <constant>0</constant> if at least one is active, or
+ non-zero otherwise. Unless <option>--quiet</option> is
+ specified, this will also print the current unit state to
+ standard output.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><command>is-failed <replaceable>PATTERN</replaceable>...</command></term>
<listitem>
- <para>Check whether any of the specified units are in a "failed" state.
- Returns an exit code 0 if at least one has failed, non-zero
- otherwise. Unless <option>--quiet</option> is specified, this
- will also print the current unit state to
- STDOUT.</para>
+ <para>Check whether any of the specified units are in a
+ "failed" state. Returns an exit code
+ <constant>0</constant> if at least one has failed,
+ non-zero otherwise. Unless <option>--quiet</option> is
+ specified, this will also print the current unit state to
+ standard output.</para>
</listitem>
</varlistentry>
<varlistentry>
<listitem>
<para>Create a snapshot. If a snapshot name is specified,
the new snapshot will be named after it. If none is
- specified, an automatic snapshot name is generated. In either
- case, the snapshot name used is printed to STDOUT, unless
- <option>--quiet</option> is specified.</para>
+ specified, an automatic snapshot name is generated. In
+ either case, the snapshot name used is printed to standard
+ output, unless <option>--quiet</option> is specified.
+ </para>
<para>A snapshot refers to a saved state of the systemd
manager. It is implemented itself as a unit that is
used to query a system password or passphrase from the
user, using a question message specified on the
command line. When run from a TTY it will query a
- password on the TTY and print it to STDOUT. When run
+ password on the TTY and print it to standard output. When run
with no TTY or with <option>--no-tty</option> it will
query the password system-wide and allow active users
to respond via several agents. The latter is
<para><command>systemd-bus-proxyd</command> will proxy D-Bus
messages to and from a bus. The will be either the system bus or
the bus specified with <option>--address</option> when that option
- is given. Messages will be proxied to/from STDIN and STDOUT, or
- the socket received through socket activation.</para>
+ is given. Messages will be proxied to/from standard input and
+ output, or the socket received through socket activation.</para>
<para>This program can be used to connect a program using classic
D-Bus to kdbus.</para>
<title>Description</title>
<para><command>systemd-cat</command> may be used to
- connect STDOUT and STDERR of a process with the
+ connect the standard input and output of a process to the
journal, or as a filter tool in a shell pipeline to
pass the output the previous pipeline element
generates to the journal.</para>
<para>If no parameter is passed,
<command>systemd-cat</command> will write
- everything it reads from standard input (STDIN) to the journal.</para>
+ everything it reads from standard input (stdin) to the journal.</para>
<para>If parameters are passed, they are executed as
- command line with standard output (STDOUT) and standard
- error output (STDERR) connected to the journal, so
+ command line with standard output (stdout) and standard
+ error output (stderr) connected to the journal, so
that all it writes is stored in the journal.</para>
</refsect1>
<title>Invoke a program</title>
<para>This calls <filename noindex='true'>/bin/ls</filename>
- with STDOUT/STDERR connected to the
+ with standard output and error connected to the
journal:</para>
<programlisting># systemd-cat ls</programlisting>
<para>Even though the two examples have very similar
effects the first is preferable since only one process
- is running at a time, and both STDOUT and STDERR are
- captured while in the second example only STDOUT is
+ is running at a time, and both stdout and stderr are
+ captured while in the second example only stdout is
captured.</para>
</refsect1>
<listitem><para>Extract the last coredump
matching specified characteristics.
- Coredump will be written on STDOUT, unless
- an output file is specified with
+ Coredump will be written on standard output,
+ unless an output file is specified with
<option>-o/--output</option>.
</para></listitem>
</varlistentry>
<title>Description</title>
<para><filename>systemd-journald</filename> is a
- system service that collects and stores logging
- data. It creates and maintains structured, indexed
- journals based on logging information that is received
- from the kernel, from user processes via the libc
+ system service that collects and stores logging data.
+ It creates and maintains structured, indexed journals
+ based on logging information that is received from the
+ kernel, from user processes via the libc
<citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- call, from STDOUT/STDERR of system services or via its
- native API. It will implicitly collect numerous meta
- data fields for each log messages in a secure and
- unfakeable way. See
+ call, from standard input and standard error of system
+ services or via its native API. It will implicitly
+ collect numerous meta data fields for each log
+ messages in a secure and unfakeable way. See
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for more information about the collected meta data.
</para>
<varlistentry>
<term><option>--debug</option></term>
<listitem>
- <para>Print debug messages to STDERR.</para>
+ <para>Print debug messages to standard error.</para>
</listitem>
</varlistentry>
<varlistentry>
<varlistentry>
<term><option>--exec-delay=</option></term>
<listitem>
- <para>Delay the execution of RUN instruction by the given
- number of seconds. This option might be useful when
- debugging system crashes during coldplug caused by loading
- non-working kernel modules.</para>
+ <para>Delay the execution of <varname>RUN</varname>
+ instruction by the given number of seconds. This option
+ might be useful when debugging system crashes during
+ coldplug caused by loading non-working kernel
+ modules.</para>
</listitem>
</varlistentry>
<varlistentry>
<varlistentry>
<term><varname>StandardError=</varname></term>
<listitem><para>Controls where file
- descriptor 2 (STDERR) of the executed
- processes is connected to. The
- available options are identical to
+ descriptor 2 (standard error) of the
+ executed processes is connected to.
+ The available options are identical to
those of
<varname>StandardOutput=</varname>,
with one exception: if set to
<varlistentry>
<term><varname>TTYPath=</varname></term>
<listitem><para>Sets the terminal
- device node to use if STDIN, STDOUT,
- or STDERR are connected to a
+ device node to use if standard input, output,
+ or error are connected to a
TTY (see above). Defaults to
<filename>/dev/console</filename>.</para></listitem>
</varlistentry>
for all file descriptors passed via
socket-based activation. If true, all
file descriptors >= 3 (i.e. all except
- STDIN/STDOUT/STDERR) will have
+ stdin, stdout, and stderr) will have
the <constant>O_NONBLOCK</constant> flag
set and hence are in
non-blocking mode. This option is only
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for details) or via the traditional
<citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style
- socket passing (i.e. sockets passed in via STDIN and
- STDOUT, using <varname>StandardInput=socket</varname>
+ socket passing (i.e. sockets passed in via standard input and
+ output, using <varname>StandardInput=socket</varname>
in the service file).</para>
</refsect1>
<para>Execute a program to determine whether there
is a match; the key is true if the program returns
successfully. The device properties are made available to the
- executed program in the environment. The program's STDOUT
+ executed program in the environment. The program's standard ouput
is available in the <varname>RESULT</varname> key.</para>
<para>This can only be used for very short-running foreground tasks. For details,
see <varname>RUN</varname>.</para>
<varlistentry>
<term><option>--debug</option></term>
<listitem>
- <para>Print debug messages to STDERR.</para>
+ <para>Print debug messages to standard error.</para>
</listitem>
</varlistentry>
<varlistentry>
~ianmdlvl / elogind.git / commitdiff