Dmenu is a fast and lightweight dynamic menu launcher for X. It can be compared to 'Quicksilver' on OS X, or 'Launchy' on Windows. With a quick keystroke, the dmenu menu appears, enabling you to type the name of a program you wish to start.
Installing dmenu is simple:
pacman -S dmenu
Once it is installed, you will need to create a shell script to run it. The following script presents some common defaults:
#!/bin/sh $(dmenu_path | \ dmenu -fn '-*-terminus-*-r-normal-*-*-120-*-*-*-*-iso8859-*' \ -nb '#000000' -nf '#FFFFFF' -sb '#0066ff')
Save the script somewhere (~/bin is a good choice) and make it executable.
Now, you will need to attach that shell script to a keystroke combination. This can be done either via your window manager or desktop environment configuration, or with a program like xbindkeys. See the Hotkeys article for more information.