[yugabyted] don't mess up shell prompt on crash

[jaki]

Running ./bin/yugabyted start on commit 06d6d8b (only one I tried) causes a crash. I am creating this issue not to focus on why the crash happens (because it may be for other reasons) but to focus on recovering from the crash.

OS: CentOS 7
commit: 06d6d8b
shells: bash 4.2.46(2)-release (x86_64-redhat-linux-gnu), zsh 5.7.1-test-3 (x86_64-pc-linux-gnu)

After the crash, if I ctrl-C, the "Running system checks" message remains. Pressing Enter or running reset don't help. The python ./bin/yugabyted start process must be killed manually (and SIGTERM doesn't work) to stop polluting the prompt. The prompts get messed up as shown below.

bash-4.2$ ./bin/yugabyted start
Starting yugabyted...
/ Running system checks...yugabyted crashed. For troubleshooting, contact us on https://www.yugabyte.com/slack or check our FAQ at https://docs.yugabyte.com/latest/faq/
\ Running system checks...^Cyugabyted stopped.
- Running system checks...bash-4.2$
| Running system checks...
- Running system checks...

~/code/yugabyte-db/1 arcpatch-D7973~1 % ./bin/yugabyted start --bind_ip 127.0.0.11
Starting yugabyted...
/ Running system checks...yugabyted crashed. For troubleshooting, contact us on https://www.yugabyte.com/slack or check our FAQ at https://docs.yugabyte.com/latest/faq/
\ Running system checks...yugabyted stopped.
- Running system checks...tch-D7973~1 %

Here is var/logs/yugabyted.log:

[yugabyted start] 2020-02-18 10:23:56,940 INFO:  | 0.1s | cmd = start using config file: <HOME>/code/yugabyte-db/1/var/conf/yugabyted.conf (args.config=None)
[yugabyted start] 2020-02-18 10:23:56,940 INFO:  | 0.1s | Starting yugabyted...
[yugabyted start] 2020-02-18 10:23:56,944 INFO:  | 0.1s | Daemon grandchild process begins execution.
[yugabyted start] 2020-02-18 10:23:56,945 INFO:  | 0.1s | yugabyted started running with PID 6955.
[yugabyted start] 2020-02-18 10:23:56,946 INFO:  | 0.1s | Running the post-installation script <HOME>/code/yugabyte-db/1/bin/post_install.sh (may be a no-op)
[yugabyted start] 2020-02-18 10:23:56,952 ERROR:  | 0.1s | Traceback (most recent call last):
  File "./bin/yugabyted", line 1024, in run
    args.func()
  File "./bin/yugabyted", line 150, in start
    self.start_processes()
  File "./bin/yugabyted", line 482, in start_processes
    self.post_install_yb()
  File "./bin/yugabyted", line 659, in post_install_yb
    post_install_script_path, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  File "/usr/share/python-2.7.17/lib/python2.7/subprocess.py", line 394, in __init__
    errread, errwrite)
  File "/usr/share/python-2.7.17/lib/python2.7/subprocess.py", line 1047, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory