diff -r 9c1d0c5ed599 -r d4f401b5f90c relpipe-data/examples-validator.xml
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/relpipe-data/examples-validator.xml	Tue Feb 05 19:18:28 2019 +0100
@@ -0,0 +1,40 @@
+<stránka
+	xmlns="https://trac.frantovo.cz/xml-web-generator/wiki/xmlns/strana"
+	xmlns:m="https://trac.frantovo.cz/xml-web-generator/wiki/xmlns/makro">
+	
+	<nadpis>Validating relational data</nadpis>
+	<perex>check whether data are in the relpipe format</perex>
+	<m:pořadí-příkladu>00500</m:pořadí-příkladu>
+
+	<text xmlns="http://www.w3.org/1999/xhtml">
+		
+		<p>
+			Just a passthrough command, so these pipelines should produce the same hash:
+		</p>
+		
+		<m:pre jazyk="bash"><![CDATA[
+relpipe-in-fstab | relpipe-tr-validator | sha512sum
+relpipe-in-fstab | sha512sum]]></m:pre>
+
+		<p>
+			This tool can be used for testing whether a file contains valid relational data:
+		</p>
+		
+		<m:pre jazyk="bash"><![CDATA[
+if relpipe-tr-validator < "some-file.rp" &> /dev/null; then
+	echo "valid relational data";
+else
+	echo "garbage";
+fi]]></m:pre>
+		
+		<p>or as a one-liner:</p>
+		
+		<m:pre jazyk="bash"><![CDATA[relpipe-tr-validator < "some-file.rp" &> /dev/null && echo "ok" || echo "error"]]></m:pre>
+		
+		<p>
+			If an error is found, it is reported on STDERR. So just omit the <code>&amp;</code> in order to see the error message.
+		</p>
+		
+	</text>
+
+</stránka>