Linux+ Chapter 07

The file descriptor stdin is represented by the number ____.

0

You can redirect a file to the standard input of a command using the ____ metacharacter.

<

You can use the BASH shell to redirect standard output and standard error from the terminal screen to a file on the filesystem using the ____ shell metacharacter followed by the absolute or relative pathname of the file.

>

____ are labels representing command input and output.

File descriptors

If you have ____ permission to a shell script, you can execute the shell script like any other executable program on the system.

Read and execute

____ are files that are typically used to create custom programs that perform administrative tasks on Linux systems.

Shell scripts

____ is the normal output of a command.

stdout

The ____ command could be used to view the contents of the environment variable that represents the BASH shell prompt.

$PS1

The ____ environment file is always executed immediately after login for all users on the system, and sets most environment variables, such as HOME and PATH.

/etc/profile

T/F - Given the syntax command && command, the command on the left of the && construct is executed only if the command on the right of the && construct completed successfully.

False

T/F - Users can create their own custom variables, called shell variables.

False

T/F - Aliases are shortcuts to commands stored in special variables that can be created and viewed using the alias command.

True

To see a list of the environment variables and their current values on a system, you can use the ____ command.

set

Any error messages generated by a command is ____.

stderr

The information that is processed by the command during execution is ____.

stdin

You can send the standard output of one command to another command as standard input using the ____ shell metacharacter.

|

T/F - You can use the sed command to remove unwanted lines of text.

True

To see a list of all exported environment and user-defined variables in the shell, you can use the ____ command.

env

____ is a filter command that takes information from standard input and sends that information to a file, as well as to standard output.

tee

The ____ command can be used to replace characters in a file sent via Standard Input.

tr

Most configuration files on Linux systems are delimited using ____ characters.

Colon

The file descriptor stderr is represented by the number ____.

2

____ are constructs that alter the flow of a program based on whether a command in the program completed successfully or based on a decision that the user makes given a question posed by the program.

Decision construct

____ are shell variables that are typically set by the system and contain information that the system and programs access regularly.

Environment variables

T/F - In a decision construct, you can have an unlimited number of if then statements.

False

T/F - To prevent a file from being cleared by the BASH shell and append output to the existing output, you can specify three > metacharacters alongside the file descriptor.

False

T/F - You are limited to using one pipe | metacharacter on the command line to pipe information from one command to another command.

False

T/F - Any command that can be executed on the command line can also be placed inside any environment file.

True

T/F - The BASH shell assumes stdout in the absence of a numeric file descriptor.

True

T/F - The ENV environment variable represents the location of the BASH run-time configuration file.

True

The test statement ____ would be used to determine if A is numerically greater than B.

[ A -gt B ]

The ____ escape sequence represents a form feed.

\f

The ____ command can be used to extract, manipulate, and format text using pattern-action statements.

awk

The first line in a shell script, which specifies the pathname to the shell that interprets the contents of the shell script, is ____.

hashpling

The ____ command counts the number of lines, words, and characters in a file.

wc