The shell by itself is already an application programming interface, but few users still query data from a command line. To adapt to the habits of current users, the dialog tool simulates the elements of a graphical interface.
The look may be a bit old-fashioned but, in terms of speed, the technology is hard to beat. If an X server is running on the system, you can provide users some additional comfort by relying on a dialog counterpart, such as Zenity or Gtkdialog (see the "Relatives" box).
To read user input, the built-in Bash read command is often used together with the echo command for simple strings. If you want to change the input prompt, enter the -p option with the new text (Listing 1).
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