CLI: Do not show column headers when not outputting to a tty:

[root@felicio ~]# tuna -q en* -Q
   # users            affinity
  54 enp1s0f0-TxRx-0     0,1,2  ixgbe
  55 enp1s0f0-TxRx-1     0,1,2  ixgbe
  56 enp1s0f0-TxRx-2     0,1,2  ixgbe
  57 enp1s0f0-TxRx-3     0,1,2  ixgbe
  58 enp1s0f0            0,1,2  ixgbe
  59 enp1s0f1-TxRx-0     0,1,2  ixgbe
  60 enp1s0f1-TxRx-1     0,1,2  ixgbe
  61 enp1s0f1-TxRx-2     0,1,2  ixgbe
  62 enp1s0f1-TxRx-3     0,1,2  ixgbe
  63 enp1s0f1            0,1,2  ixgbe
  66 enp7s0              0,1,2  atl1c
[root@felicio ~]# tuna -q en* -Q | head -4
  54 enp1s0f0-TxRx-0     0,1,2  ixgbe
  55 enp1s0f0-TxRx-1     0,1,2  ixgbe
  56 enp1s0f0-TxRx-2     0,1,2  ixgbe
  57 enp1s0f0-TxRx-3     0,1,2  ixgbe
[root@felicio ~]#

[root@felicio ~]# tuna -t xfs-d* -P
                      thread       ctxt_switches
    pid SCHED_ rtpri affinity voluntary nonvoluntary             cmd
  459    OTHER     0  0,1,2,3         2            1   xfs-data/dm-1
  654    OTHER     0  0,1,2,3         2            0   xfs-data/sda1
  669    OTHER     0  0,1,2,3         2            0   xfs-data/dm-2
[root@felicio ~]# tuna -t xfs-d* -P | head
  459    OTHER     0  0,1,2,3         2            1   xfs-data/dm-1
  654    OTHER     0  0,1,2,3         2            0   xfs-data/sda1
  669    OTHER     0  0,1,2,3         2            0   xfs-data/dm-2
[root@felicio ~]#

Useful, for instance, when using wc to count how many IRQs or threadas match
some filters.

Signed-off-by: Arnaldo Carvalho de Melo <acme@felicio.ghostprotocols.net>
diff --git a/tuna-cmd.py b/tuna-cmd.py
index f85b629..270e769 100755
--- a/tuna-cmd.py
+++ b/tuna-cmd.py
@@ -305,7 +305,8 @@
 	
 	has_ctxt_switch_info = ps[1]["status"].has_key("voluntary_ctxt_switches")
 	try:
-		ps_show_header(has_ctxt_switch_info, cgroups)
+		if sys.stdout.isatty():
+			ps_show_header(has_ctxt_switch_info, cgroups)
 		ps_show(ps, affect_children, thread_list,
 			cpu_list, irq_list, show_uthreads, show_kthreads,
 			has_ctxt_switch_info, sock_inodes, sock_inode_re, cgroups)
@@ -334,7 +335,8 @@
 	if not irqs:
 		irqs = procfs.interrupts()
 
-	print "%4s %-16s %8s" % ("#", _("users"), _("affinity"),)
+	if sys.stdout.isatty():
+		print "%4s %-16s %8s" % ("#", _("users"), _("affinity"),)
 	sorted_irqs = []
 	for k in irqs.keys():
 		try: