In computing, alias is a command in various command-line interpreters (shells), which enables a replacement of a word by another string.

[2] Aliasing functionality in the MS-DOS and Microsoft Windows operating systems is provided by the DOSKey command-line utility.

Older versions of the Bourne shell did not offer aliases, but it did provide functions, which are more powerful than the csh alias concept.

[3] Non-persistent aliases can be created by supplying name/value pairs as arguments for the alias command.

Instead, this must be done by adding items to the collection $PSDefaultParameterValues, one of the PowerShell preference variables.

The usual syntax is to define the first alias with a trailing space character.

For example, with this alias: ls-more /etc /usr expands to ls /etc /usr | more to list the contents of the directories /etc and /usr, pausing after every screenful.