set netns in the same command line

namespace_demo/topo-square.sh

@@ -29,14 +29,12 @@ PID=$$
 
 # A-br0-B
 xunshare B -- ip link set lo up
-xnsenter B -- ip link add ba type veth peer BA
-xnsenter B -- ip link set BA netns $PID
+xnsenter B -- ip link add ba type veth peer BA netns $PID
 xnsenter B -- ip link set ba up
 ip link set BA up
 
 xunshare A -- ip link set lo up
-xnsenter A -- ip link add ab type veth peer AB
-xnsenter A -- ip link set AB netns $PID
+xnsenter A -- ip link add ab type veth peer AB netns $PID
 xnsenter A -- ip link set ab up
 ip link set AB up
 
@@ -46,14 +44,12 @@ ip link set AB master br0
 ip link set br0 up
 
 # A-br1-C
-xnsenter A -- ip link add ac type veth peer AC
-xnsenter A -- ip link set AC netns $PID
+xnsenter A -- ip link add ac type veth peer AC netns $PID
 xnsenter A -- ip link set ac up
 ip link set AC up
 
 xunshare C -- ip link set lo up
-xnsenter C -- ip link add ca type veth peer CA
-xnsenter C -- ip link set CA netns $PID
+xnsenter C -- ip link add ca type veth peer CA netns $PID
 xnsenter C -- ip link set ca up
 ip link set CA up
 
@@ -63,14 +59,12 @@ ip link set AC master br1
 ip link set br1 up
 
 # C-br2-D
-xnsenter C -- ip link add cd type veth peer CD
-xnsenter C -- ip link set CD netns $PID
+xnsenter C -- ip link add cd type veth peer CD netns $PID
 xnsenter C -- ip link set cd up
 ip link set CD up
 
 xunshare D -- ip link set lo up
-xnsenter D -- ip link add dc type veth peer DC
-xnsenter D -- ip link set DC netns $PID
+xnsenter D -- ip link add dc type veth peer DC netns $PID
 xnsenter D -- ip link set dc up
 ip link set DC up
 
@@ -80,13 +74,11 @@ ip link set DC master br2
 ip link set br2 up
 
 # B-br3-D
-xnsenter B -- ip link add bd type veth peer BD
-xnsenter B -- ip link set BD netns $PID
+xnsenter B -- ip link add bd type veth peer BD netns $PID
 xnsenter B -- ip link set bd up
 ip link set BD up
 
-xnsenter D -- ip link add db type veth peer DB
-xnsenter D -- ip link set DB netns $PID
+xnsenter D -- ip link add db type veth peer DB netns $PID
 xnsenter D -- ip link set db up
 ip link set DB up