Keyboard shortcut to scroll Terminal one line at a time

Solution 1:

If you look at the View menu, it has bindings for Line up and Line down, but no help for the icons.

I do not have a Mac keyboard, so there are no icons "at hand".

However, those icons are shown in Terminal Keyboard Shortcuts, allowing me to see that the binding is

CommandAltPageUp and
CommandAltPageDown

for line-up and line-down, respectively.

Solution 2:

In older versions of OS X, the shortcut used to be CommandUpArrow and CommandDownArrow. If you want this shortcut restored to what you used to use, you can do so in System Preferences > Keyboard > Shortcuts > App Shortcuts. There, you can create two new shortcuts for the application "Terminal" for menu titles "Line Up" and "Line Down". This will override the CommandAltPageUp and CommandAltPageDown default shortcuts.