Consider the following commands: 

What is displayed when this sequence of commands is executed using the bash shell? 

Answer options:

A. Hello, world
B. cat: cannot open file1
C. cat: cannot open file1Hello, world
D. cat: cannot open file1 Hello, World
E. bash: syntax error near unexpected token `&&`

B

First line (rm file1) deletes/removes file1. Second line captures the text into file2. The first part of line 3 (cat file1) fails as the file1 does not exist. The && (AND) operator will ensure that the third line fails. The result of line 3 will be the result of first part of line 3 (cat file1). Note: cat - concatenate files and print on the standard output Note #1: 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. 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. Note #2 (on exit status): Zero means command executed successfully, if exit status returns non-zero value then your command failed to execute.