</varlistentry>
</variablelist>
+
+ <para>
+ Invoking &xmlcatalog; non-interactively without a designated action
+ (imposed with options like <option>--add</option>) will result in a lookup
+ of the catalog entry for <replaceable>ENTITIES</replaceable> in the
+ catalog denoted with <replaceable>CATALOGFILE</replaceable>. The
+ corresponding entries will be output to the command line. This mode of
+ operation, together with <option>--shell</option> mode and non-modifying
+ (i.e. without <option>--noout</option>) direct actions, allows for
+ a special shortcut of the void <replaceable>CATALOGFILE</replaceable>
+ specification (possibly expressed as "" in the shell
+ environment) appointing the default system catalog. That simplifies the
+ handling when its exact location is irrelevant but the respective built-in
+ still needs to be consulted.
+ </para>
</refsect1>
<refsect1 id="shell">
<term><option>public <replaceable>PUBLIC-ID</replaceable></option></term>
<listitem>
<para>
- Execute a Formal Public Identifier look-up of the catalog entry
+ Execute a Formal Public Identifier lookup of the catalog entry
for <replaceable>PUBLIC-ID</replaceable>. The corresponding entry will be
output to the command line.
</para>
<term><option>system <replaceable>SYSTEM-ID</replaceable></option></term>
<listitem>
<para>
- Execute a Formal Public Identifier look-up of the catalog entry
+ Execute a Formal Public Identifier lookup of the catalog entry
for <replaceable>SYSTEM-ID</replaceable>. The corresponding entry will be
output to the command line.
</para>