Requires python2.7 breaks on python3

[majorcrash]

On Ubuntu 18.04

1. Does not run as is on vanilla ubuntu 18.04. The default path for python is /usr/bin/python3
2. Manually install python2.7 then the shebang needs to be altered to run:
   #!/usr/bin/python2.7
3. If shebang is altered to /usr/bin/python3 the following error is produced:
   sudo ./pvshrink /dev/sdf
   Traceback (most recent call last):
   File "./pvshrink", line 55, in
   for seg in pvs.split("\n"):
   TypeError: a bytes-like object is required, not 'str'

[thefantas]

To make it work with python3.7 modify this line.
Line 55:

for seg in pvs.split("\n"):

Replace:

for seg in pvs.decode().split("\n"):

[devZer0]

that's not enough to make pvshrink python compatible, there are other errors

[devZer0]

after some search i found a version which seems to correctly being ported to python3 and which apparently also still works with python2 :

https://github.com/sensimple-contrib/pvshrink

these are the 2 commits which make it python2 compatible:

https://github.com/sensimple-contrib/pvshrink/commits?author=jsalatiel

could you apply those to your version @pdw-mb ?

what about submitting this upstream to the lvm2 project at http://sourceware.org/lvm2/ ?

this is a very useful tool !

[enriluis]

nice!
thanks !

[albfan]

This deserves a PR! #3