All of OneLiner's functionality is realized from the Run dialog that is performed by doing a WindowsKey-R keypress, which is a default keypress in Windows XP, or by clicking the "Start" menu button and then clicking on the "Run..." option. The two features it provides are a search and an immediate execution.
The search feature is done by entering a "!" character followed by some text in the "Run..." dialog (ie. WindowsKey-R). This will search through the Start Menu and Internet Explorer favorites for the subject text, and display all matches in a dialog for you to select one to execute. For instance, entering "!word" might result in a list containing "Microsoft Word for Windows" and "Wordpad", amongst others. You would simply double-click the entry in the list, or click it once and then click the "OK" button to execute it. See figures 1 and 2 for screen prints of a sample.

Figure 1: Windows "Run..." dialog initiated by the WindowsKey-R keypress, showing a search for all Start Menu and Internet Explorer Favorites having the text "word" in it.

Figure 2: A dialog showing the results of the OneLiner search; to execute a listed item, double-click it, or use the arrow-keys to select and hit the Return key. Likewise, you could left-click on the item, and click the OK button.
An immediate execution of a shortcut can be accomplished by entering text in the "Run..." dialog for which a Start Menu shortcut or Internet Explorer favorite has the subject text encapsulated between parentheses. For instance, if you have a Start Menu item named "WordPad (wp)", and you do a WindowKey-R and enter "wp" at the "Run..." prompt, then WordPad will be executed without further inquiry. See figure 3 for a screen print of a sample.

Figure 3: Shows an attempt to execute something in the Start Menu or Internet Explorer Favorites that has "(wp)" in the name.
For convenience, you could perform a search first (ie. "!word"), and from the resulting list, right-click and select the "Properties" option in the context menu. This will allow you to modify the shortcut's name so that you can possibly add a command to it (ie. change "Wordpad" to "Wordpad (wp)"). See figures 4 and 5 for an example of this.

Figure 4: Shows the context menu that will appear when right-clicking on one of the resulting entries.

Figure 5: Shows the standard properties dialog that will appear when selecting "Properties" in the context menu, whereby you can modify the name of the item and add a keyword between parentheses.
Known Issue: If you change the name of an item in the resulting list by bringing up the Properties dialog, and attempt to double-click the item in the resulting list afterward, an exception will occur. This is because the list has the old name of the item, and now cannot find it. As a workaround, you will need to close the current results list, and then just redo the WindowsKey-R and use the new keyword as the command. This issue will be resolved in a future version of the product.