An AND list has the form
command1 && command2
command2 is executed if, and only if, command1 succeeds
An OR list has the form
command1 || command2
command2 is executed if, and only if, command1 fails
list is a sequence of one or more pipelines separated by one
of the operators `;', `&', `&&',
or `||', and optionally terminated by one of `;',
`&', or a
Of these list operators, `&&' and `||' have equal precedence, followed by `;' and `&', which have equal precedence.
If a command is terminated by the control operator `&', the shell executes the command asynchronously in a subshell. This is known as executing the command in the background. The shell does not wait for the command to finish, and the return status is 0 (true).