Make it work on linux too.

More error checking.

event/trafgen/tg-install

 #!/bin/sh
 #	cd from <builddir>/event/trafgen to testbed/event/trafgen
+
+if [ -x /usr/bin/fetch ]; then
+    fetch=/usr/bin/fetch
+elif [ -x /usr/bin/wget ]; then
+    fetch=/usr/bin/wget
+else
+    echo "ERROR: tg-install: need either 'fetch' or 'wget' installed"
+    exit 1
+fi
+
 if [ ! -d $1/tg2.0/src ]; then
     echo "Downloading tg2.0 source from www.emulab.net to $1 ..."
     cd $1
-    fetch http://www.emulab.net/tg2.0.tar.gz
+    $fetch http://www.emulab.net/tg2.0.tar.gz
     if [ $? -ne 0 ]; then
          echo "Failed..."
          echo "Downloading tg2.0 source from www.postel.org to $1 ..."
-         fetch http://www.postel.org/tg/tg2.0.tar.gz
+         $fetch http://www.postel.org/tg/tg2.0.tar.gz || {
+	     echo "ERROR: tg-install: $fetch failed"
+	     exit 1
+	 }
     fi
     echo "Unpacking/patching tg2.0 source ..."
-    tar xzf tg2.0.tar.gz
-    patch -p0 < tg.patch
+    tar xzf tg2.0.tar.gz || {
+        echo "ERROR: tg-install: tar failed"
+	exit 1
+    }
+    patch -p0 < tg.patch || {
+        echo "ERROR: tg-install: patch failed"
+	exit 1
+    }
     rm -f tg2.0.tar.gz tg2.0/*/*/*.orig
 fi
-
+exit 0