package A and that package requires package B to run, dselect will
warn you of the problem and will most likely suggest a solution. If
package A conflicts with package B (i.e., if they are mutually
exclusive), you will be asked to decide between them.
Let's look at the top two lines of the Select screen. This header reminds
us of some of the special keys listed in Table 3.1.

Table 3.1: Special dselect keys
+------------------------------------------------------+
| Key | Description |
|------+-----------------------------------------------|
| + | Select a package for installation. |
|------+-----------------------------------------------|
| = | Place a package on hold |
|------+-----------------------------------------------|
| - | Remove a package. |
|------+-----------------------------------------------|
| _ | Remove a package and its configuration files. |
|------+-----------------------------------------------|
| i, I | Toggle/cycle information displays. |
|------+-----------------------------------------------|
| o, O | Cycle through the sort options. |
|------+-----------------------------------------------|
| v, V | A terse/verbose toggle. |
+------------------------------------------------------+

Table 3.2 lists the states that dselect uses to denote the status of each
package it is aware of.

Table 3.2: dselect Package States