How to use ASCII characters on KDE?

1-Go to

System settings->Input devices->Keyboard->Advanced->Position of the compose key

2-Choose a option available, like Right Control
3-Test it typing

Righ_Control =  c

4-You get

€ 

Arcam Sapientia

This is the equivalent to the Alt on Windows systems.

Check KDE version by terminal

kded4 --version

Arcam Sapientia

If not works, try:

kded --version

How to prompt for a password when running a command or script?

kdesudo "<Full command>"

Example

1 - Open the run command with Alt+F2
2 - To reboot (needs root), for example, type:

kdesudo "shutdown -r now"

3- Type your root password and hit Return
4 - Your system will reboot after this

 Arcam Sapientia

You can use this on scripts to prompt for a pass when it is needed.

#!/bin/sh

clementine

kdesudo "shutdown -r 00:00"

This will open the clementine music player and reboot at 00:00 time.