Implemented --delay.

src/parallel

@@ -498,6 +498,7 @@ sub options_hash {
 	 "basenameextensionreplace|bner=s" => \$opt::basenameextensionreplace,
 	 "seqreplace=s" => \$opt::seqreplace,
 	 "jobs|j=s" => \$opt::P,
+	 "delay=f" => \$opt::delay,
 	 "load=s" => \$opt::load,
 	 "noswap" => \$opt::noswap,
 	 "max-line-length-allowed" => \$opt::max_line_length_allowed,
@@ -613,7 +614,7 @@ sub get_options_from_array {
 sub parse_options {
     # Returns: N/A
     # Defaults:
-    $Global::version = 20121126;
+    $Global::version = 20121127;
     $Global::progname = 'parallel';
     $Global::infinity = 2**31;
     $Global::debug = 0;
@@ -3906,6 +3907,9 @@ sub start {
 	    $job->set_timeout($opt::timeout);
 	    $Global::timeoutq->insert($job);
 	}
+	if($opt::delay) {
+	    ::usleep($opt::delay*1000);
+	}
 	return $job;
     } else {
 	# No more processes

src/parallel.pod

@@ -426,6 +426,13 @@ occurs as a line of input, the rest of the input is ignored.  If
 neither B<-E> nor B<-e> is used, no end of file string is used.
 
 
+=item B<--delay> I<secs> (alpha testing)
+
+Delay starting next job I<secs> seconds. GNU B<parallel> will pause
+I<secs> seconds after starting each job. I<secs> can be less than 1
+seconds.
+
+
 =item B<--dry-run>
 
 Print the job to run on stdout (standard output), but do not run the

src/parallel.texi

@@ -1086,7 +1086,7 @@ will generate the files:
 and
 
 @verbatim
-  parallel --results foo/bar echo {1} {2} ::: 1 2 ::: 3 4
+  parallel --results foo/bar echo {1} {2} ::: I II ::: III IIII
 @end verbatim
 
 will generate the files:

testsuite/tests-to-run/parallel-local164.sh

@@ -5,6 +5,9 @@ SERVER2=parallel-server2
 
 # -L1 will join lines ending in ' '
 cat <<'EOF' | sed -e s/\$SERVER1/$SERVER1/\;s/\$SERVER2/$SERVER2/ | parallel -j10 -k -L1
+echo "### Test --delay"
+seq 9 | /usr/bin/time -f %e  parallel -j3 --delay 0.3 true {} 2>&1 | perl -pe 's/.[0-9]+$//'
+
 echo '### Test -k 5'; 
   sleep 5
 

testsuite/wanted-results/parallel-local164

@@ -1,3 +1,5 @@
+### Test --delay
+3
 ### Test -k 5
 ### Test -k 3
 ### Test -k 4