/alias is a IRC command that replaces a command or string of commands of your choosing with a shortcut.
For example, if you wanted to /kick and temporarily /ban a user Bob, you could do it the long way:
- /mode #channelname +b Bob
- /kick #channelname Bob
- Wait a bit.
- /mode #channelname -b Bob
Or you could make an alias: "/alias X mode #channelname +b $0;kick #channelname $0;timer 120 mode #channelname -b $0"
In this command, $0 is a wildcard; it will be filled by whatever name you type after your alias: "/X Bob" will ban Bob for a count of 120 seconds. /X EvilTroll will ban EvilTroll for 120 seconds.
Be warned, an /alias will be lost at the end of your session unless you /save it.