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<title>s6-linux-init: the s6-linux-init-echo program</title>
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<h1> The <tt>s6-linux-init-echo</tt> program </h1>
<p>
s6-linux-init-echo writes its arguments to stdout.
</p>
<h2> Interface </h2>
<pre>
s6-linux-init-echo [ -n ] [ -s sep ] <em>args...</em>
</pre>
<p>
s6-linux-init-echo writes its arguments <em>args</em> to stdout, separated with spaces.
</p>
<h2> Options </h2>
<ul>
<li> <tt>-n</tt> : do not output a trailing newline. </li>
<li> <tt>-s</tt> <em>sep</em> : separate arguments with the <em>sep</em>
character instead of a space. </li>
</ul>
<h2> Notes </h2>
<ul>
<li> Strange, and appalling, as it may seem for such a simple task, there is
no way to ensure that the <tt>echo</tt> program will behave consistently from
Unix system to Unix system - and even from Linux distribution to Linux
distribution. Despite there being a
<a href="//pubs.opengroup.org/onlinepubs/9699919799/utilities/echo.html">standard</a>
for it, the <tt>echo</tt> commands in GNU coreutils, busybox, toybox, sbase, and
other implementations basically all exhibit different behaviours. Every shell has
a built-in <tt>echo</tt> command, that fails to follow the POSIX standard. <tt>echo</tt>
is the prime example of the consequences of the blatant disregard of early Unices
for cross-system compatibility, and its followup as a turf war between GNU and the
rest of the Linux world. As a distribution-agnostic software developer, it is ironically
impossible to rely on a definite behaviour of the <tt>echo</tt> command on every
supported system, and that is why s6-linux-init provides its own implementation.
Fortunately, it is very easy to do so, with minimal overhead. </li>
<li> This command is an exact duplicate of the
<a href="//skarnet.org/software/s6-portable-utils/s6-echo.html">s6-echo</a> command
provided in the <a href="//skarnet.org/software/s6-portable-utils/">s6-portable-utils</a>
package. It was decided <em>not</em> to have a dependency from s6-linux-init to
s6-portable-utils: that dependency would arguably be a higher cost than the small
amount of code duplication. </li>
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