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Correct choice is (c) elif

Easiest EXPLANATION: if-else STATEMENTS MAKES TWO-way decisions depending on the fulfillment of certain CONDITIONS. But if we want to check more than two conditions we can use elif statement. For example,

Right option is (c) $?

The EXPLANATION is: The parameter $? STORES the exit status of the last command. It displays the value if the command SUCCEEDS and a non ZERO value if it fails.

The correct option is (B) DOLLAR 0

The EXPLANATION is: There are some special parameters used by the shell. One of which is $0 which STORES the NAME of the program.

Right answer is (B) FI

The best I can explain: if and ELSE statements are used for making two-way decisions. Every if is CLOSED with the corresponding fi. If we don’t do this we’ll encounter an ERROR.

Correct CHOICE is (a) cmd1 && cmd2

To explain: The SHELL provides two OPERATORS that allow conditional EXECUTION –the && and ||. The syntax for using these operators is:

Correct choice is (B) $#

To explain: $# is used for storing the NUMBER of arguments specified. It lets us design scripts that CHECK whether the right number of arguments have been ENTERED. For example, the FOLLOWING script shows the use of positional parameters:

Right option is (B) False

Best explanation: || is an operator used by the SHELL for CONDITIONAL execution. It plays an INVERSE role in which the second COMMAND is executed only when the first fails.

The CORRECT answer is (a) True

Explanation: The shell provides two operators that allow conditional EXECUTION, one of which is &&. It delimits two commands; the second COMMAND is EXECUTED only when the FIRST command succeeds.

Right OPTION is (d) && and ||

The EXPLANATION: The operators && and || are used for LOGICAL EXECUTION i.e. they act as AND, OR CONDITION respectively. The syntax for using these operators is:

Correct choice is (a) True

The explanation: A SINGLE read STATEMENT can be used with one or more variables to let us enter multiple arguments. For EXAMPLE,

read FirstNameLastName

The correct ANSWER is (C) $*

The EXPLANATION: There are some special parameters USED by the shell. One of which is $*, which stores the complete set of POSITIONAL parameters as a single string.

The CORRECT choice is (d) $1

To ELABORATE: COMMAND line arguments are stored into positional parameters. The first argument is read by the shell into the PARAMETER $1, second argument in $2 and so on.

Correct OPTION is (a) True

The explanation: read command is the shell’s internal tool for TAKING input from the USER i.e. it makes the scripts INTERACTIVE.

Correct choice is (c) sh

The EXPLANATION: We know that shell SCRIPTS are executed by a child shell. But we can also explicitly SPAWN a child of our own choice by using the sh COMMAND along with script name as an argument. When used in this way, the interpreter LINE is ignored by the shell.

The correct choice is (a) chmod +X

The BEST I can explain: Before we run the script, it is ESSENTIAL to make the script executable first. After that INVOKE the script NAME to run the script. For making the script executable, we have to use chmod +x script_name.

The correct answer is (c) read

For explanation I WOULD SAY: read command is USED for making SCRIPTS INTERACTIVE. It is used for taking input from the user. Input supplied from the keyboard is entered into the variable used with the read command. For example,

Right option is (a) True

Easy explanation: Shell scripts are executed in a separate child process, and this sub-shell NEED not be of the same type as our login shell. In other words, EVEN if our login shell is bourne, we can USE a KORN sub-shell to run our SCRIPT.

Right option is (b) False

For EXPLANATION: It’s not mandatory to save SCRIPT files with .SH extension but we do so for our own convention as it makes it easy to MATCH them with WILDCARDS.

The correct choice is (c) a file containing a series of COMMANDS

Explanation: When we have to EXECUTE a series of commands altogether, we store them in a file which is itself executed as a shell script. A shell script is basically a computer PROGRAM designed to be run by the UNIX shell.