Can we type NUL character (HEX 0) from the keyboard?
Most of the printable character starts from HEX value 20.
egres
See if this control character works:
Ctrl+@
jeevan
Ctrl+spacebar works for both Windows and Linux platforms.
Simon
According to Wikipedia
Ctrl+SPACE works on many terminals (worked for me).
Press and hold Alt and type Num Pad 0Num Pad 0Num Pad 0 then release Alt
Note: You must use the 0 key on the numeric key pad (a regular 0 key won't work for this), and you have to hold down Alt the whole time. The keystroke isn't emitted until you release the Alt key.
In editing fields in SQL Server, it is Control Zero (Ctrl + 0)
来源：https://stackoverflow.com/questions/9124786/how-to-simulate-nul-character-from-keyboard