diff --git a/etc/controlDict b/etc/controlDict
index 2176dc2f6d..99ac513fe0 100644
--- a/etc/controlDict
+++ b/etc/controlDict
@@ -74,10 +74,10 @@ OptimisationSwitches
     nProcsSimpleSum 0;
 
     // Force dumping (at next timestep) upon signal (-1 to disable)
-    writeNowSignal              -1; // 10;
+    writeNowSignal              -1; // 10; // SIGUSR1
 
-    // Force dumping (at next timestep) upon signal (-1 to disable) and exit
-    stopAtWriteNowSignal        -1;
+    // Force dumping and exit (at next timestep) upon signal (-1 to disable)
+    stopAtWriteNowSignal        -1; // 12; // SIGUSR2
 
     // Default dictionary scoping syntax
     inputSyntax slash;
diff --git a/src/OSspecific/POSIX/signals/sigStopAtWriteNow.H b/src/OSspecific/POSIX/signals/sigStopAtWriteNow.H
index abc1ef1239..9c5edf982b 100644
--- a/src/OSspecific/POSIX/signals/sigStopAtWriteNow.H
+++ b/src/OSspecific/POSIX/signals/sigStopAtWriteNow.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -25,10 +25,20 @@ Class
     Foam::sigStopAtWriteNow
 
 Description
-    Signal handler for interrupt defined by
-        OptimisationSwitches::stopAtWriteNowSignal
+    Signal handler to write and exit when the stopAtWriteNowSignal is sent.
 
-    Write and stop the job.
+    stopAtWriteNowSignal is set in etc/controlDict::OptimisationSwitches, e.g.
+    \verbatim
+    OptimisationSwitches
+    {
+        .
+        .
+        // Force dumping and exit (at next timestep) upon signal (-1 to disable)
+        stopAtWriteNowSignal        12; // SIGUSR2
+        .
+        .
+    }
+    \endverbatim
 
 SourceFiles
     sigStopAtWriteNow.C
diff --git a/src/OSspecific/POSIX/signals/sigWriteNow.H b/src/OSspecific/POSIX/signals/sigWriteNow.H
index e1d97068c5..92ab6f1e91 100644
--- a/src/OSspecific/POSIX/signals/sigWriteNow.H
+++ b/src/OSspecific/POSIX/signals/sigWriteNow.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -25,9 +25,20 @@ Class
     Foam::sigWriteNow
 
 Description
-    Signal handler for interrupt defined by OptimisationSwitches::writeNowSignal
+    Signal handler to write when the writeNowSignal is sent.
 
-    Write once and continue.
+    writeNowSignal is set in etc/controlDict::OptimisationSwitches, e.g.
+    \verbatim
+    OptimisationSwitches
+    {
+        .
+        .
+        // Force dumping (at next timestep) upon signal (-1 to disable)
+        writeNowSignal              10; // SIGUSR1
+        .
+        .
+    }
+    \endverbatim
 
 SourceFiles
     sigWriteNow.C