Aliases are defined with the alias command, and may be removed with the unalias command.
After history expansion, if the first word on the command line has been defined as an alias, the text for which it is an alias for is substituted. The alias may contain references to the arguments provided on the command line, in which case the appropriate arguments are substituted in. If there are no such references, any arguments given are appended to the end of the alias text.
If a command line starts with a backslash `\' any alias substitution is inhibited.