Add 'whenjobs --whisper' which lets you set variables "quietly".

[whenjobs.git] / tools / whenjobs.pod

diff --git a/tools/whenjobs.pod b/tools/whenjobs.pod
index 14ca141..6d2a554 100644 (file)
--- a/tools/whenjobs.pod
+++ b/tools/whenjobs.pod
@@ -267,6 +267,25 @@ Display all the variables and their values, in the format C<name=value>.
 
 Display the name and version of the program and exit.
 
+=item B<--whisper> variable=value [variable=value ...]
+
+This works the same way as the I<--set> option, but with the
+difference that jobs' when clauses are not reevaluated.  In other
+words, the variables are set, but "quietly" so as not to trigger any
+jobs to run.
+
+Note that this can lead to some unexpected results: one case is a
+when job such as:
+
+ when changed a || changed b : << ... >>
+
+If C<a> is changed using I<--whisper>, then the job will not run.
+
+But later on, if C<b> is set but to the same value that it already has
+(ie. not changed), the job will run because the whole when-clause is
+reevaluated and C<a> is found to have changed since the last run of
+the job.
+
 =back
 
 =head1 REFERENCE