chain Fish commands via `&&` or `||`

Fish doesn't have a special syntax for a logical AND (&&) or a logical OR (||).

Instead, you can use the commands and and or, which verify the previous command's exit status and act accordingly:

command1
and command2

command1
or command2

Furthermore – just like in bash – you can use a semicolon ; to execute two commands one after the other:

command1 ; command2

This allows using a more familiar syntax:

command1 ;and command2
command1 ;or command2

See http://fishshell.com/docs/current/tutorial.html#tut_combiners

The logical operators you're used to, are supported since fish 3.0.0, released on 2018-12-28.

From the v3 release notes:

fish now supports && (like and), || (like or), and ! (like not), for better migration from POSIX-compliant shells (#4620).

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