Found that sudo sysctl -a does not complete on macOS Catalina 10.15.5 Beta 19F53f. Killing with -9 also does not help to terminate the process. Create a feed back FB7653964.
[FB7653964]sudo sysctl -a does not complete on macOS Catalina 10.15.5 Beta 19F53f
The system was shutdown for a week and booted up now. The same command is able to finish successfully, now.
When compared the differences in outputs, observed that the first point of command getting stuck is at this place:
...
439c439
< vm.copied_on_read: 2
---
> vm.copied_on_read: 1
482,486c482,1327
< ^C^C^C^C^C^C
<
< ^C^C^C
<
<
---
> vfs.generic.hfs.kdebug.allocation: 0
...