I am running Ubuntu 14.04 with a terminal window. Because I type fairly quickly I sometimes use ctrl-u to wipe out my partially entered line which works great. Once my partially typed line is wiped out, I am back at my command prompt and am ready to enter a command.

But sometimes I accidently press ctrl-shift-u and then immediately start typing (thinking I am at the command prompt again). Instead of wiping out the line, the characters I type are underlined and sometimes get converted into hex characters, or sometimes if I type too many characters when it is in this mode, my keyboard completely locks up. Even if I open an new terminal window I still can't type. The only solution is a reboot.

What am I activating when I type ctrl-shift-u followed by other characters? And is there a way for me to configure this feature off so I don't lock myself up?

(Perhaps I should type more carefully so I don't accidently hit ctrl-shift)

Thanks for your help, Robert

  • I don't know why it is slowing your system, but you are activating unicode input.
    – user448115
    May 13, 2016 at 18:48

1 Answer 1


I just found out that IBus was activating, and it substitutes Unicode characters. I guess pressing more than 4 characters locks up keyboard input.

I found out how to disable IBus completely. I went to the Ubuntu system settings, selected Language Support. Under Keyboard input method system I changed IBus to none, and my ctrl-Shift-U lockup problems are now gone.

Thank you Adonis for directing me to the solution.

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