Linux Essentials Test 3

Use _______________________ to copy the public key to the correct location on a remote system. (spelling, case, and syntax count)

ssh-copy-id

What is the command to generate a public/private keypair for ssh? (spelling, case, and syntax count)

ssh-keygen

Job Control

____________________ is a feature of the shell which allows a single shell instance to run and manage multiple commands. (There are two words in this answer)

Daemons

_________________ are processes that wait or run in the background performing various tasks.

What tcp port does ssh use by default?

22

Parts of the environment of a process

- Local and global variables - All current scheduling context - Allocated system resources, such as file descriptors and network ports

Various aspects of the ssh server can be modified in the configuration file __________________.

/etc/ssh/sshd_config

&

Any command or pipeline can be started in the background by appending this character to the end of the command line.

What does the following systemd service state mean? static

Can not be enabled, but may be started by an enabled unit automatically.

Zombie (Z)

EXIT_ZOMBIE - A child process signals its parent as it exits. All resources except for the process identity (PID) are released.

True or False: Secure shell (sshd) cannot be used to run a command on a remote server.

False

/etc/ssh/ssh_host_key*

Host keys are stored in______________________ on the SSH server. (not the client).

ps

The command to see a list of the currently running background processes.

PermitRootLogin

The parameter in the ssh server configuration used to allow the root user to log in remotely to the server.

PasswordAuthentication

The parameter in the ssh server file that enables password authentication for logging in remotely.

pkill

This command can send signals to multiple processes and uses advanced selection criteria.

bg

To start a suspended process running in the background, use this command with the same job ID.

restart

To stop, then start, the service in a single command means to _____________ the service

True or False: A process includes address space.

True

What does the following systemd service state mean? enabled

Will be started at boot time.

What does the following systemd service state mean? disabled

Will not be started at boot time.

The command root would use to disable the cupsd service; spelling, case, and syntax count.

systemctl disable cupsd

Write the command root would use to enable the sshd service; spelling, case, and syntax count:

systemctl enable sshd

Command which needs to be executed once the changes are saved to the sshd configuration file? (spelling, case, and syntax count)

systemctl reload sshd

Write the command root would use to restart the httpd service; spelling, case, and syntax count:

systemctl restart httpd

Write the command root would use to check the status of the sshd service; spelling, case, and syntax count:

systemctl status sshd

True or False: A process has properties including ownership credentials and read-only privileges.

True

What does the following systemd service state mean? active (waiting)

Running but waiting for an event.

What does the following systemd service state mean? active (running)

Running with one or more continuing processes.

What does the following systemd service state mean? active (exited)

Successfully completed a one-time configuration.

systemd

System startup and server processes in RHEL7 are managed by ________________. This program provides a method for activating system resources, server daemons, and other processes, both at boot time and on a running system.

Sleeping (S)

TASK_INTERRUPTIBLE - The process is waiting for some condition: a hardware request, system resource access, or signal. When an event or signal satisfies the condition, the process returns to Running.

Running (R)

TASK_RUNNING - The process is either executing on a CPU or waiting to run. Process can be exeecuting user routines or kernel routines (system calls), or be queued and ready when in the Running (or Runnable) state.

Stopped (T)

TASK_STOPPED - The process has been Stopped (suspended), usually by being signaled by a user or another process. The process can be continued (resumed) by another signal to return to Running.

Sleeping (D)

TASK_UNINTERRUPTIBLE - The process is also Sleeping, but unlike s state, will not respond to delivered signals. Used only under specific conditions in which process interruption may cause an unpredictable device state.

Service

A _________________ often refers to one or more daemons, but starting or stopping a _________________________ may instead make a one-time change to the state of the system, which does not involve leaving a daemon process running afterward. (The same word goes in both blanks)

process

A ______________________ is a running instance of a launched, executable program.

fg

A background job can be brought to the foreground by using the this command with its job ID (%job number).

Socket

A daemon uses a ____________________ to listen for connections.

reload

Command to issue instructions for a service to read and reload its configuration file without a complete stop and start. The process ID will not change.

A user's public key.

Copied to systems which a user wants to log into, and used to verify the private key.

passphrase

During ssh key generation, there is the option to specify a ___________ which must be provided in order to access your private key.

What does the following systemd service state mean? inactive

Not running.

aux

The ____________________ command displays all processes, with columns in which users will be interested, and includes processes without a controlling terminal. It is an old Unix command that is still popular today. Your answer is case sensitive and must only include the command and the option(s).

~/.ssh/known_hosts

The first time a user uses ssh to connect to a particular server, the ssh command stores the server's public key in the user's _____________________ file.

OpenSSH

The software implementation of the Secure Shell software used in RHEL7.

True or False: A process includes of one or more execution threads of program code.

True

What does the following systemd service state mean? loaded

Unit configuration file has been processed.

A user's private key.

Used as the authentication credential and must be kept secret and secure.

Command for user joeblow from his local account to login using ssh to his account on the bigbrain server. (spelling, case, and syntax count)

ssh bigbrain