parallel: --tty allows for more programs accessing /dev/tty in parallel.

doc/release_new_version

@@ -210,6 +210,11 @@ Quote of the month:
 <<>>
 
 New in this release:
+
+* --tty allows for more programs accessing /dev/tty in parallel. Some programs require tty access without using it.
+
+* env_parallel --session will record names in current environment in $PARALLEL_IGNORED_NAMES and exit. It is only used with env_parallel, and can work like --record-env but in a single session.
+
 https://comquest.in/training
 https://bash-prompt.net/guides/parallell-bash/
 https://blog.uta.edu/xus/2017/09/29/an-easy-way-to-run-parallel-jobs-on-stampede2/

src/env_parallel.pod

@@ -27,7 +27,20 @@ B<env_parallel> is 100 ms slower at startup than pure GNU
 B<parallel>, and takes up to 30% longer to start a job (typically 15 ms).
 
 Due to the problem with environment space (see below) the recommended
-usage is:
+usage is either:
+
+  # Do --record-env into $PARALLEL_IGNORED_NAMES
+  env_parallel --session
+
+  # Define whatever you want to use
+  alias myalias=echo
+  myvar=it
+  myfunc() { myalias $1 $myvar works.; }
+
+  # env_parallel will not export names in $PARALLEL_IGNORED_NAMES
+  env_parallel -S localhost myfunc ::: Yay,
+
+Or:
 
   # Record the "clean" environment (this only needs to be run once)
   env_parallel --record-env
@@ -42,7 +55,7 @@ usage is:
   # Use --env _ to only transfer the names not in the "empty" environment
   env_parallel --env _ -S localhost myfunc ::: Yay,
 
-In B<csh>:
+In B<csh> B<--session> is not supported:
 
   # Record the "clean" environment (this only needs to be run once)
   env_parallel --record-env

src/parallel

@@ -2449,7 +2449,6 @@ sub __RUNNING_THE_JOBS_AND_PRINTING_PROGRESS__ {}
 #    $Global::host{$sshlogin} = Pointer to SSHLogin-object
 #    $Global::total_running = total number of running jobs
 #    $Global::total_started = total jobs started
-#    $Global::tty_taken = is the tty in use by a running job?
 #    $Global::max_procs_file = filename if --jobs is given a filename
 #    $Global::JobQueue = JobQueue object for the queue of jobs
 #    $Global::timeoutq = queue of times where jobs timeout
@@ -2471,7 +2470,6 @@ sub init_run_jobs {
     # Returns: N/A
     $Global::total_running = 0;
     $Global::total_started = 0;
-    $Global::tty_taken = 0;
     $SIG{USR1} = \&list_running_jobs;
     $SIG{USR2} = \&toggle_progress;
     if(@opt::basefile) { setup_basefile(); }
@@ -3927,7 +3925,6 @@ sub reaper {
     # Uses:
     #   %Global::sshmaster
     #   %Global::running
-    #   $Global::tty_taken
     #   $opt::timeout
     #   $Global::timeoutq
     #   $opt::halt
@@ -3969,10 +3966,6 @@ sub reaper {
 
         debug("run", "seq ",$job->seq()," died (", $job->exitstatus(), ")");
         $job->set_endtime(::now());
-        if($stiff == $Global::tty_taken) {
-            # The process that died had the tty => release it
-            $Global::tty_taken = 0;
-        }
         my $sshlogin = $job->sshlogin();
         $sshlogin->dec_jobs_running();
         if($job->should_be_retried()) {
@@ -8588,7 +8581,7 @@ sub start {
 	}
 	$job->set_fh(0,"w",$stdin_fh);
 	if($opt::tee) { $job->set_virgin(0); }
-    } elsif ($opt::tty and not $Global::tty_taken and -c "/dev/tty" and
+    } elsif ($opt::tty and -c "/dev/tty" and
 	     open(my $devtty_fh, "<", "/dev/tty")) {
 	# Give /dev/tty to the command if no one else is using it
 	# The eval is needed to catch exception from open3
@@ -8605,7 +8598,6 @@ sub start {
 		|| ::die_bug("open3-/dev/tty");
 	    1;
 	};
-	$Global::tty_taken = $pid;
 	close $devtty_fh;
 	$job->set_virgin(0);
     } else {

src/parallel.pod

@@ -2041,6 +2041,8 @@ Record names in current environment in B<$PARALLEL_IGNORED_NAMES> and
 exit. Only used with B<env_parallel>. Aliases, functions, and
 variables with names in B<$PARALLEL_IGNORED_NAMES> will not be copied.
 
+Only supported in B<Ash, Bash, Dash, Ksh, Sh, and Zsh>.
+
 See also B<--env>, B<--record-env>.
 
 
@@ -2328,13 +2330,13 @@ Silent.  The job to be run will not be printed. This is the default.
 Can be reversed with B<-v>.
 
 
-=item B<--tty>
+=item B<--tty> (alpha testing)
 
-Open terminal tty. If GNU B<parallel> is used for starting an
+Open terminal tty. If GNU B<parallel> is used for starting a program
-interactive program then this option may be needed. It will start only
+that accesses the tty (such as an interactive program) then this
-one job at a time (i.e. B<-j1>), not buffer the output (i.e. B<-u>),
+option may be needed. It will default to starting only one job at a
-and it will open a tty for the job. When the job is done, the next job
+time (i.e. B<-j1>), not buffer the output (i.e. B<-u>), and it will
-will get the tty.
+open a tty for the job.
 
 You can of course override B<-j1> and B<-u>.