diff --git a/doc/developer/advance.tex b/doc/developer/advance.tex
index 9cdae7b648b7fe6ac7012808e09b58cb536a5c99..3917f576cf2a906a48c419899453a9d80f77f535 100644
--- a/doc/developer/advance.tex
+++ b/doc/developer/advance.tex
@@ -1168,18 +1168,20 @@ or
   the suite. This directive is only
   usable in a \texttt{test\_config}\codeidx{test\_config}
   configuration file.
-\item The \texttt{FILTER}\nscodeidx{Test!Directive}{FILTER} command performs
-  a transformation on the test result files before the comparison from the
+\item The \texttt{FILTER}\nscodeidx{Test!Directive}{FILTER} directive specifies
+  a transformation on the test result files before the comparison to the the
   oracles.
-  The filter command read the result from the standard input and the oracle
-  will be compared from the standard output of that command.
-  In such a command, the  \texttt{@PTEST\_ORACLE@} variable is set to the
+  The filtering command read the result from the standard input and the oracle
+  will be compared with the standard output of that command.
+  In such a directive, the \texttt{@PTEST\_ORACLE@} variable is set to the
   basename of the oracle.
   That allows to perform a \texttt{diff} command with the oracle of another
   test configuration:
   \begin{code}
     FILTER: diff --new-file @PTEST_DIR@/oracle_configuration/@PTEST_ORACLE@
   \end{code}
+  Chaining multiple filter commands is possible in defining several \texttt{FILTER} directives,
+  and an empty command drops the previous \texttt{FILTER} directives.
 \end{itemize}
 
 \begin{important}
diff --git a/ptests/ptests.ml b/ptests/ptests.ml
index 7831fc5c551767f472bafc9f92a208cf8d8b803b..b98589f11bc1df78bcb3c4425c22ce516dfbb46a 100644
--- a/ptests/ptests.ml
+++ b/ptests/ptests.ml
@@ -340,6 +340,8 @@ let example_msg =
      EXIT: <number>      @[<v 0># Defines the exit code required for the next sub-test commands.@]@  \
      FILTER: <cmd>       @[<v 0># Performs a transformation on the test result files before the comparison from the oracles.@ \
      # The oracle will be compared from the standard output of the command: cat <test-output-file> | <cmd> .@ \
+     # Chaining multiple filter commands is possible in defining several FILTER directives.@ \
+     # An empty command drops the previous FILTER directives.@ \
      # Note: in such a command, the @@PTEST_ORACLE@@ variable is set to the basename of the oracle.@ \
      # That allows to perform a 'diff' command with the oracle of another test configuration:@ \
      #    FILTER: diff --new-file @@PTEST_DIR@@/oracle_configuration/@@PTEST_ORACLE@@ @]@  \