Type null character in terminal

In Linux, any special character can be literally inserted on the terminal by pressing Ctrl+v followed by the actual symbol. null is usually ^@ where ^ stands for Ctrl and @ for whatever combination on your keyboard layout that produces @.

So on my keyboard I do: Ctrl+v followed by Ctrl+Shift+@ and I get a ^@ symbol with a distinguished background color. This means it's a special character and not just ^ and @ typed in.

Edit: Several years later and a few input variations implemented by different terminals using keyboard layouts that require pressing Shift to access @.

• Ctrl+v followed by Ctrl+Shift+@
• Ctrl+v followed by Shift+@ without releasing Ctrl.
• Ctrl+Shift+v followed by @ without releasing Ctrl+Shift.
• Ctrl+Shift release Shift and re-press Shift keeping both Ctrl+Shift pressed followed by v and finally @. Seen in some terminals that implement a special input on Ctrl+Shift.

$ echo -e "this is a sentence \0 test123"this is a sentence  test123

The null here ^^ IS NOT visible

$ echo -e "this is a sentence \0 test123" | cat --show-nonprintingthis is a sentence ^@ test123

But it IS here ^^

But maybe you did not want this for a script?

Apparently you can type this character with ^@ on some character sets. This wikipedia article on the null character may be helpful.