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 3.2.3 Lists of Commands
 -----------------------
 
 A `list' is a sequence of one or more pipelines separated by one of the
 operators `;', `&', `&&', or `||', and optionally terminated by one of
 `;', `&', or a `newline'.
 
    Of these list operators, `&&' and `||' have equal precedence,
 followed by `;' and `&', which have equal precedence.
 
    A sequence of one or more newlines may appear in a `list' to delimit
 commands, equivalent to a semicolon.
 
    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).  When job
 control is not active ( Job Control), the standard input for
 asynchronous commands, in the absence of any explicit redirections, is
 redirected from `/dev/null'.
 
    Commands separated by a `;' are executed sequentially; the shell
 waits for each command to terminate in turn.  The return status is the
 exit status of the last command executed.
 
    AND and OR lists are sequences of one or more pipelines separated by
 the control operators `&&' and `||', respectively.  AND and OR lists
 are executed with left associativity.
 
    An AND list has the form
      COMMAND1 && COMMAND2
 
 COMMAND2 is executed if, and only if, COMMAND1 returns an exit status
 of zero.
 
    An OR list has the form
      COMMAND1 || COMMAND2
 
 COMMAND2 is executed if, and only if, COMMAND1 returns a non-zero exit
 status.
 
    The return status of AND and OR lists is the exit status of the last
 command executed in the list.
 

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