head	1.6;
access;
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	pkgsrc-2013Q2:1.6.0.30
	pkgsrc-2013Q2-base:1.6
	pkgsrc-2012Q4:1.6.0.28
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	pkgsrc-2011Q4:1.6.0.26
	pkgsrc-2011Q4-base:1.6
	pkgsrc-2011Q2:1.6.0.24
	pkgsrc-2011Q2-base:1.6
	pkgsrc-2009Q4:1.6.0.22
	pkgsrc-2009Q4-base:1.6
	pkgsrc-2008Q4:1.6.0.20
	pkgsrc-2008Q4-base:1.6
	pkgsrc-2008Q3:1.6.0.18
	pkgsrc-2008Q3-base:1.6
	cube-native-xorg:1.6.0.16
	cube-native-xorg-base:1.6
	pkgsrc-2008Q2:1.6.0.14
	pkgsrc-2008Q2-base:1.6
	pkgsrc-2008Q1:1.6.0.12
	pkgsrc-2008Q1-base:1.6
	pkgsrc-2007Q4:1.6.0.10
	pkgsrc-2007Q4-base:1.6
	pkgsrc-2007Q3:1.6.0.8
	pkgsrc-2007Q3-base:1.6
	pkgsrc-2007Q2:1.6.0.6
	pkgsrc-2007Q2-base:1.6
	pkgsrc-2007Q1:1.6.0.4
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	TNF:1.1.1;
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comment	@# @;


1.6
date	2006.11.05.09.09.20;	author rillig;	state dead;
branches;
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1.5
date	2006.11.05.07.24.04;	author rillig;	state Exp;
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1.4
date	2006.10.20.10.14.44;	author rillig;	state Exp;
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1.3
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1.1.1.1
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desc
@@


1.6
log
@Removed the pkgsrc portability book, as editing DocBook XML is no fun at
all. The contents has been moved to the NetBSD wiki at:

    http://wiki.aydogan.net/index.php/The_pkgsrc_portability_guide
@
text
@<!-- $NetBSD: utilities.xml,v 1.5 2006/11/05 07:24:04 rillig Exp $ -->

<chapter id="utilities">
<title>Command line utilities</title>

<para>This chapter collects the various bugs and peculiarities of the
<ulink url="http://www.opengroup.org/onlinepubs/000095399/idx/utilities.html">POSIX-like
utilities</ulink> on the platforms.</para>

<sect1 id="util.ls">
<title>ls</title>

<para>On MacOS&nbsp;X, <literal>ls</literal> does not return an error
code when the file to be listed does not exist. On some other platforms,
it does.</para>

</sect1>

<sect1 id="util.sh">
<title>sh</title>

<sect2 id="util.sh.ext">
<title>Non-standard extensions</title>

<para>The variable <varname>RANDOM</varname> is an addition of
<filename>ksh</filename>, and <filename>bash</filename> can do it as
well.</para>

<para>The command <command>[[</command> is an addition of
<filename>ksh</filename>, and <filename>bash</filename> can do it as
well.</para>

</sect2>

<sect2 id="util.sh.netbsd">
<title>NetBSD</title>

<para>On NetBSD, have a look at <ulink
url="http://www.netbsd.org/cgi-bin/query-pr-list.pl?state=open&amp;state=closed&amp;state=feedback&amp;text=/bin/sh&amp;category=bin">the
various PRs</ulink> to see what's wrong with the shell.</para>

</sect2>

<sect2 id="util.sh.solaris">
<title>Solaris</title>

<para>On Solaris, <filename>/bin/sh</filename> is missing some features
that POSIX <ulink
url="http://www.opengroup.org/onlinepubs/000095399/utilities/sh.html">requires</ulink>
for the sh utility:</para>

<programlisting>
    $ if ! false; then echo ok; fi
    !: not found

    $ echo ${PWD%/}
    bad substitution

    $ foo=$(true)
    syntax error: `foo=$' unexpected
</programlisting>

<para>There is another sh implementation in
<filename>/usr/xpg4/bin</filename>, which implements these features.
However, many shell scripts and other programs have /bin/sh
hard-coded.</para>

<para>Another incompatibility is this:</para>

<programlisting>
    $ set -- foo bar baz; echo "before: $#"; set --; echo "after: $#"
    before: 3
    after: 3
</programlisting>

<para>All(?) other shells, including <filename>/usr/xpg4/bin/sh</filename>,
reply with <quote>after: 0</quote>.</para>

<para>On Solaris, both <filename>/bin/sh</filename> and
<filename>/usr/xpg4/bin/sh</filename> cannot handle empty for loops.</para>

<programlisting>
    $ for i in ; do echo "i=$i"; done
    syntax error: `;' unexpected
</programlisting>

<para>The work-around is either to add some dummy arguments or to save
the list of things in a variable. Looping over empty lists is no
problem. But note that the various parameter expansions that are applied
here differ in this case.</para>

<programlisting>
    $ things=""; for i in $things; do echo "i=$i"; done
</programlisting>

<sect3 id="util.sh.solaris.glob">
<title>Globbing problems with quoting and hidden files</title>

<programlisting>
    rm -rf "testdir"
    mkdir "testdir"
    touch "testdir/.file"

    x="."
    y=".file"
    echo "=== x and y quoted"
    ls "$x"/*/"$y"
    echo "=== only x quoted"
    ls "$x"/*/$y
    echo "=== nothing quoted"
    ls $x/*/$y
</programlisting>

<para>The result of running this code with <filename>/bin/sh</filename>
is that in the first case, the result of the globbing expansion is
<quote><literal>./*/.file</literal></quote>, while in the two other
cases, it is the correct
<quote><literal>./testdir/.file</literal></quote>. This does only happen
when y starts with a dot, that is, for hidden files.</para>

</sect3>
</sect2>
</sect1>

<sect1 id="util.test">
<title>test</title>

<sect2 id="util.test.options">
<title>Supported options</title>

<para>It is expected that the <emphasis>test</emphasis> utility fully
supports the POSIX standard. Any deviations from it are recorded in the
<quote>Unsupported</quote> column.</para>

<table>
<title>Supported options of the <emphasis>test</emphasis> utility</title>
<tgroup cols="2">
<thead>
<row><entry>Platform</entry><entry>Unsupported</entry><entry>Supported</entry><entry>Extensions</entry></row>
</thead>
<tbody>
<row><entry>AIX-4.3-powerpc</entry><entry></entry><entry>bcdefghLnprstuwxz</entry><entry>k</entry></row>
<row><entry>IRIX-6.5-mipseb</entry><entry></entry><entry>bcdefghLnprstuwxz</entry><entry>k</entry></row>
<row><entry>Linux-2.6.*-*</entry><entry></entry><entry>bcdefgLnprSstuwxz</entry><entry>GkO nt ot ef</entry></row>
<row><entry>NetBSD-3.0-*</entry><entry></entry><entry>bcdefgLnprSstuwxz</entry><entry>GkO nt ot ef</entry></row>
<row><entry>SunOS-5.10-* /bin/sh</entry><entry>eS</entry><entry>bcdfghLnprstuwz</entry><entry>k</entry></row>
<row><entry>SunOS-5.10-* /bin/test</entry><entry></entry><entry>bcdefgLnprSstuwxz</entry><entry>aGkOo nt ot ef</entry></row>
</tbody>
</tgroup>
</table>

<para>Remarks:</para>

<itemizedlist>

<listitem><para>On Solaris-5.10-*, the behavior of the
<literal>-f</literal> operator depends on the value of the environment
variable <varname>PATH</varname>.</para></listitem>

<listitem><para>On Solaris-5.10-*, <filename>/usr/ucb/test</filename>
behaves like the builtin command in <filename>/bin/sh</filename>. On the
other hand, <filename>/usr/bin/test</filename> conforms to
POSIX.</para></listitem>

</itemizedlist>

</sect2>

<sect2 id="util.test.ext">
<title>Non-standard extensions</title>

<para>The Bourne Again Shell (bash) allows the binary operator
<literal>==</literal> to be used as an alias for <literal>=</literal>.
This leads to problems when programs using this feature are ported to
other platforms. By the way, not even the GNU coreutils have that
<quote>feature</quote>, it's really only Bash that does. After all,
there is no apparent benefit for having two names for the same
operator.</para>

</sect2>

<sect2 id="util.test.bugs">
<title>Bugs</title>

<para>On NetBSD upto X.Y (see <ulink url="&u.PR;34646">PR 34646</ulink>), the &man.test.1; utility cannot
handle the following:</para>

<programlisting>
    test ! = foo
</programlisting>

<para>POSIX <ulink
url="http://www.opengroup.org/onlinepubs/000095399/utilities/test.html">requires</ulink>
that when test is called with three arguments, the second operand is
checked first to see whether it is a binary operator. On NetBSD, the
unary <quote>!</quote> operator takes precedence.</para>

</sect2>
</sect1>
</chapter>
@


1.5
log
@On the platforms to which I have access, I checked the features of the
"test" utility. Except for the "-e" operator on Solaris, it seems that
we can use everything that is specified in POSIX.
@
text
@d1 1
a1 1
<!-- $NetBSD: utilities.xml,v 1.4 2006/10/20 10:14:44 rillig Exp $ -->
@


1.4
log
@ls(1) on MacOS X returns 0 on error.
@
text
@d1 1
a1 1
<!-- $NetBSD: utilities.xml,v 1.3 2006/10/07 08:13:21 rillig Exp $ -->
d128 41
@


1.3
log
@Collected some non-standard extensions for sh(1).
@
text
@d1 1
a1 1
<!-- $NetBSD: utilities.xml,v 1.2 2006/10/06 22:18:33 rillig Exp $ -->
d10 9
d131 1
a131 1
<para>The Bourne Again Shell (Bash) allows the binary operator
@


1.2
log
@Provided a link to the Open Group's utilities web page.

Tested "test foo == bar" with test(1) from the GNU coreutils. It does
_not_ know the "==" operator.
@
text
@d1 1
a1 1
<!-- $NetBSD: utilities.xml,v 1.1.1.1 2006/10/06 21:10:41 rillig Exp $ -->
d13 13
@


1.1
log
@Initial revision
@
text
@d1 1
a1 1
<!-- $NetBSD$ -->
d7 2
a8 1
POSIX-like utilities on the platforms.</para>
d112 4
a115 2
other platforms. Furthermore, there is no apparent benefit for having
two names for the same operator.</para>
@


1.1.1.1
log
@Imported portability-book.

The pkgsrc portability book covers many of the platform-specific issues
that are useful when writing programs that are portable to a great
number of UNIX-like operating systems.
@
text
@@