There are also times when you might want to include material from other sources in your messages, and c/c/p allows you to do this easily.
If you make webpages, the ability to copy information from another location into your own page is a real timesaver.
Copying only a portion of a viewed webpage or post, or received mail, requires the use of the Find key to create a highlight, which you can then extend to cover everything you want to copy.
Now, while you still have the text temporarily stored in the "clipboard" of your terminal's RAM memory, move the cursor down to the box below, and use Cmd-V to paste the text into it.
If you're typing a document (email, newsgroup post), you can select text for highlighting from the current cursor location, by holding down the Shift key and using the Right, Left, Up, or Down Arrow (to highlight a character at a time right or left, or a line at a time up or down), or the Up or Down Scroll keys (to highlight a screen's worth of text at a time, with each press of the Scroll key). You can highlight all your writing by using Cmd-A.
Try it out. Put the cursor into the box below, and move the cursor to the beginning of the text. Then, while holding down the Shift key, press the Right Arrow key a few times to extend the highlight a letter at a time rightward. Then, with Shift held down, press the Down Arrow twice to extend the highlight downward. At any point, you would be able to use Cmd-C to copy or Cmd-X to cut whatever you have highlighted.
Many times, you'll want to copy just part of an email message, newsgroup post, or webpage text, rather than "grabbing" the entire thing. To select only the portion of the text you want to copy, use Find and search for the word or phrase that appears at either the beginning or end of the section you want to copy; that word or phrase will automatically be highlighted. Then, while holding down the Shift key, use the Arrow or Scroll keys to extend the highlight until the entire section of text you want to copy is selected then press Cmd-C to copy it. Once you've got it copied, go into your email or newsgroup posting screen (or webpage editor), and use Cmd-V to paste it. (You can still highlight the entire page, or an area of the page (if there are frames or a sidebar) for copying by pressing Cmd-A.)
Why not try it out, with this paragraph? Hit Find (or press Cmd-F) and type in Why not then hit Return. That will highlight the first two words of this paragraph; then while holding down the Shift key, press the down key until you've highlighted the entire paragraph. Now, press Cmd-C to copy the text.
Move the cursor into the box below, and press Cmd-V to paste the paragraph of text into it.
Whatever is copied or cut will be stored in RAM memory, until you either copy or cut something else, or power off the terminal or switch users.
Practice this all over the place until it becomes second nature. Go to a newspaper site online, for instance, and use Find to select a paragraph in an article, highlight the entire paragraph, use Cmd-C to copy it, then go to Mail and paste the paragraph into a Write screen. Use this feature to copy part of a received email for inclusion with your reply experiment.