ROS noetic + Ubuntu20.04报错：

mc@ubun:~$ rosrun tf view_frames
Listening to /tf for 5.0 seconds
Done Listening
b'dot - graphviz version 2.43.0 (0)\n'
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/tf/view_frames", line 119, in <module>
    generate(dot_graph)
  File "/opt/ros/noetic/lib/tf/view_frames", line 89, in generate
    m = r.search(vstr)
TypeError: cannot use a string pattern on a bytes-like object

查了一下，search函数需要输入str类型数据，而vstr（有可能？）不是str类型，所以需要把

m = r.search(vstr)

改成，

m = r.search(str(vstr))

如下，

        try:
            vstr = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()[1]
        except OSError as ex:
            print("Warning: Could not execute `dot -V`.  Is graphviz installed?")
            sys.exit(-1)
        v = distutils.version.StrictVersion('2.16')
        r = re.compile(".*version (\d+\.?\d*)")
        print(vstr)
        m = r.search(str(vstr)) 

不过同样官方的说法如下，

将

m = r.search(vstr)

改为，

m=r.search(vstr.decode('utf-8'))

我试了一下，两种都能给出正确的结果。