Chapter 9: Managing Linux Processes (combined)

process priority

A number assigned to a process, used to determine how many time slices on the processor that process will receive; the higher the number, the lower the priority.

foreground process

A process for which the BASH shell that executed it must wait for its termination.

background process

A process that does not require the BASH shell to wait for its termination. Upon execution, the user receives the BASH shell prompt immediately.

zombie process

A process that has finished executing but whose parent has not yet released its PID; the zombie still retains a spot in the kernel's process table.

at

A system administrator wants to schedule a task to run at 11 pm, but knows that she will not be in the office at that time. Which of the following commands can she use to schedule this task to run that night while she is at home?

True

As daemon processes are not associated with terminals, you must use an option such as -e alongside the ps command to view them. True False

There is a question mark in the TTY column.

When you run the ps command, how are daemon processes recognized? The terminal is listed as tty0. There is a question mark in the TTY column. There is an asterisk in the STIME column. There is a "d" for daemon in the terminal identification column.

parent process

A process that has started other processes (child processes).

/etc/cron.deny

A system administrator wants to allow most users to be able to run cron jobs, but wants to specifically prevent a couple of users from doing so. Which of the following files could the administrator edit to disallow these users from creating cron jobs?

crontab

What command is used to view and modify user jobs scheduled to run with cron? hat command is used to view and modify user jobs scheduled to run with cron? crontab cron ps sched

jobs

Which command can be used to see processes running in the background? bg jobs ps -% fg

/var/spool/at

A directory that stores the information used to schedule commands using the at daemon on Fedora systems.

/var/spool/cron/atjobs

A directory that stores the information used to schedule commands using the at daemon on Ubuntu systems.

user process

A process begun by a user and which runs on a terminal.

child process

A process that was started by another process (parent process).

process

A program currently loaded into physical memory and running on the system.

program

A structured set of commands stored in an executable file on a filesystem. A program can be executed to create a process.

process ID (PID)

A unique identifier assigned to every process as it begins.

You can use the Ctrl+z key combination and the bg command.

How can you bypass the wait function and send a user process to the background? This cannot happen once a process is executing; it can be done only when the command is started by placing an ampersand (&) after it. This cannot happen; only daemon processes can run in the background. You can use the ps command. You can use the Ctrl+z key combination and the bg command.

killall command

The command that kills all instances of a process by command name.

kill command

The command used to kill or terminate a process.

crontab command

The command used to view and edit user cron tables. daemon process A system process that is not associated with a terminal. options (-e: creates -l: list contents)

process state

The current state of the process on the processor; most processes are in the sleeping or running state.

pstree

What command is used to display the lineage of a process by tracing its PPIDs until the init daemon?

daemon process

What is the name given to a process not associated with a terminal? child process parent process user process daemon process

9

What kill level signal cannot be trapped? 1 9 3 15

/var/spool/cron/username

Where are individual user tasks scheduled to run with the cron daemon stored on a Fedora system? /etc/crontab /etc/cron/username /var/spool/cron /var/spool/cron/username

d. /var/spool/cron/atjobs

Where are scheduled commands stored on Ubuntu Linux systems?

ps

Which command entered without arguments is used to display a list of processes running in the current shell? pgrep list pid ps

top

Which command is used to gain real-time information about processes running on the system, with the most processor-intensive processes listed at the beginning of the list? ps ps -elf top pstree

nohup

Which of the following can be used preceding a command to prevent a process from terminating when the parent process terminates?

isof

Which of the following commands can be used to see files that are currently being used by a specific process ID (PID)?

renice -12

Which of the following commands will most likely increase the chance of a process receiving more time slices? renice 0 renice 15 renice -12 renice 19

kill -9 1357

Which of the following commands will send a process's resources to /dev/null to kill the process for process ID 1357? *Force kill of process using PID

19

Which of the following is the highest value that can be set for the nice value which would result in a greater chance of a lower priority? 19 15 -12 0

pstree command

A command that displays processes according to their lineage, starting from the init daemon.

parent process ID (PPID)

The PID of the parent process that created the current process.

crontab -l

Which of the following commands will show the current user cron jobs that have been created for the currently logged in user?

zombie

Which of the following states describe a process that is waiting for a parent process to release its PID?

init/systemd

Which process has a PID of 1 and a PPID of 0? the kernel itself ps init/systemd top

fg

After a background process has been started, what command can be used to move it to the foreground?

trapping

The process of ignoring a kill signal.

at daemon (atd)

The system daemon that executes tasks at a future time; it is configured with the at command.

foreground (fg) command

The command used to run a background process in the foreground.

background (bg) command

The command used to run a foreground process in the background. (&)

at command

The command used to schedule commands and tasks to run at a preset time in the future.

jobs command

The command used to see the list of background processes running in the current shell.

all instances of a process with the same name matched by a regular expression

The pkill command terminates _________. all instances of a process with the same PPID all instances of a process with the same PID all instances of a process with the same priority all instances of a process with the same name matched by a regular expression

cron table

A file specifying tasks to be run by the cron daemon; there are user cron tables and system cron tables.

parent process ID

Every process has a process ID and a_______. fork process daemon child process parent process ID

forking

The act of creating a new BASH shell child process from a parent BASH shell process.

time slice

The amount of time a process is given on a CPU in a multiprocessing operating system.

schedule processes to run at a single instance in the future

The at command is used to _______________. schedule processes to run periodically in the background schedule processes to run periodically on a recurring basis in the future schedule processes to run at a single instance in the future schedule processes to run in the foreground

renice command

The command used to alter the nice value of a process currently running on the system.

nice command

The command used to change the priority of a process as it is started.

top command

The command used to give real-time information about the most active processes on the system; it can also be used to renice or kill processes.

ps command

The command used to obtain information about processes currently running on the system.

r

While the top command is running, what key can be pressed to change the nice value of a process?

/var/spool/cron/crontabs

A directory that stores user cron tables on an Ubuntu system.

is a rogue process

A process spawning or initiating another process is referred to as _____. is a zombie process is an orphaned process has a PPID of Z is a rogue process

rogue process

A process that has become faulty in some way and continues to consume far more system resources than it should.

/var/spool/cron

A directory that stores user cron tables on a Fedora system.

/etc/at.allow

A file listing all users who can use the at command. /etc/at.deny A file listing all users who cannot access the at command. /etc/cron.allow A file listing all users who can use the cron command. /etc/cron.d A directory that contains additional system cron tables. /etc/cron.deny A file listing all users who cannot access the cron command.

-20 and 19

Nice values are used to affect process priorities using a range between _____________. 0 and 20 0 and -19 -19 and 20 -20 and 19

/etc/crontab

The default system cron table.

cron daemon (crond)

The system daemon that executes tasks repetitively in the future and that is configured using cron tables.

forking

The term used to describe a process spawning or initiating another process is referred to as_________.

kill signal

The type of signal sent to a process by the kill command; different kill signals affect processes in different ways.

nice value

The value that indirectly represents the priority of a process; the higher the value, the lower the priority. (-n) also NIC

False

To kill a process running in the background, you must place a % character before its process ID. True or False?

If /etc/at.allow exists, only users listed in it can use the at command. If /etc/cron.allow exists, only users listed in it can use the cron command. If /etc/cron.deny exists and /etc/cron.allow does not exist, any user not listed in /etc/cron.deny can use the cron command.

Which of the following statements is true? (Choose all that apply.) If /etc/at.allow exists, only users listed in it can use the at command. If /etc/cron.allow exists, only users listed in it can use the cron command. If /etc/cron.deny exists and /etc/cron.allow does not exist, any user not listed in /etc/cron.deny can use the cron command. If /etc/cron.allow and /etc/cron.deny exist, only users listed in the former can use the cron command and any listed in the latter are denied access to the cron command. If a user is listed in both /etc/cron.allow and /etc/cron.deny, then /etc/cron.deny takes precedence and the user cannot access the crontab command.