I am trying to find some Unix tool to input any Unicode key. I am fine with X application or console but I use Vi/m and it may have this property. For example, suppose I want to input key
"U+0303" or the key
"U+007E" in Unicode.
You should get something below, source, with the unicodes:
U+0303 ◌̃ combining tilde and U+007E ~
I am looking for a general tool, not be depended on certain kbd layouts. It is actually better if it is was some very basic tool without unnecessary bells-and-whistles. The simplest win.