How can I use && with my own functions?

Running this prints out both statements

#!开发者_高级运维/bin/bash
echo "Hello" && echo "World"

However, running this only prints out "Hello"

#!/bin/bash
message() {
  echo "Hello"
  return 1
}
message && echo "World"

Why doesn't this work and how can I change my script so that it does?

An "exit" value of 0 means success while anything else means failure. and the && operator doesn't execute the right hand side if the left hand side fails (that is if it returns non-zero)

So change the return 1 to return 0

return 1 (or anything else which is not 0) means false to bash, which means the second command will not be called.

Use return 0 (this means true), or chain them using other operators (like || or ;.)

_{As mentioned in a comment, technically bash doesn't have boolean values, and && and || are not described as "boolean short-circuit operators" in the manual, but "control operators". As a && b means "run b if and only if a succeeded", and "success" is defined as a zero exit code (and the command true always returns 0, while false returns 1), the net effect is the same as what I described above.}

In bash a return value of 1 indicates an error.

Try return 0

&& executes the second instruction only if the first one is successful, i.e. has a 0 result

Remove the return statement in your message() function.