Most administrators know to type the question mark (?) at the IOS command line to see a list of possible commands. However, you can also use it in other useful ways.
For example, you can type it after a command to view the possible parameters. Or, if you know part of a command, you can type it after one or more letters to see all the possible commands that begin with that letter.
In a sense, “?” can be seen as a complement to the Tab key; if you’ve entered part of a command, you can complete it automatically just by pressing the Tab key, or press “?” if you’re not sure how to complete it.
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