102-500 Questions and Answers

/etc/alias

~/.alias

/etc/mail/forwarders

~/.forward

~/.vacation

date -d '+ 1 day'

hwclock --systohc --localtime

ntpdate pool.ntp.org

time hwclock

cupsreject -c -r hello HPLaserjet4

cupsreject -p -m hello HPLaserjet4

cupsdisable -c -r hello HPLaserjet4

cupsdisable -p -m hello HPLaserjet4

sshd

ssh-agent

ssh-keygen

ssh-add

core

edquota

ulimit

quota

debug

lsof

nessus

strace

traceroute

umask

usermod

ulimit

passwd

chage

It must be sent by any SSH client in addition to a user key in order to identify the client's host.

It provides the server's identity information to connecting SSH clients.

It is the root key by which all user SSH keys must be signed.

It authenticates any user that logs into a remote machine from the key's host.

It is used by system services like cron, syslog or a backup job to automatically connect to remote hosts.

/etc/ssh/sshd_config

/etc/ssh/ssh

/etc/ssh/server

/etc/ssh/ssh_config

/etc/ssh/ssh_server

ssh --port 2222 example.com

ssh -p 2222 example.com

ssh -o Port=2222 example.com

ssh -o GatewayPort=2222 example.com

ssh example.com:2222

find /usr -uid 0 -perm +4000

find -user root +mode +s /usr

find -type suid -username root -d /usr

find /usr -ls \*s\* -u root

find /usr -suid -perm +4000

It is incompatible with syslog and cannot be installed on a system using regular syslog.

It only processes messages of systemd and not messages of any other tools.

It can pass log messages to syslog for further processing.

It maintains metadata such as _UID or _PID for each message.

It supports syslog facilities such as kern, user, and auth.

Connecting local USB devices to remote applications.

Accessing graphical applications on a remote host.

Replacing Xorg as local X11 server.

Downloading and locally installing applications from a remote machine.

Uploading and running a binary program on a remote machine.

Manage and adjust bandwidth used by TCP services.

Bind a network service to a TCP port.

Encapsulate TCP messages in IP packets.

Add SSL support to plain text TCP services.

Limit access to a network service.

mail.*/var/log/maillogmail,crit@logger.example.org

mail.*/var/log/maillogmail.critsyslog://logger.example.org

mail/var/log/maillogmail.crit@logger.example.org

mail.*/var/log/maillogmail.crit@logger.example.org

mail */var/log/maillogmail crit@logger.example.org

The timestamp of the user’s last login

The user’s private SSH keys

The hashed password of the user

The numerical user ID (UID)

The path to the user’s home directory

iburst

quickstart

fast

D. fsync

flood

Commands the user can run using sudo.

The absolute path to the user’s home directory.

Which printers are available for the new user.

The SSH keys used to login to the new account.

The numeric user ID (UID) of the user.

result: 6 5 4

result: 1 2 3 4 5 6

result: 3 4 5 6 2 1

result: 6 5 4 3 2 1

result: 3 2 1

Timer units can only be defined within a service unit’s file.

The command executed by the timer is specified in the timer unit’s [Cmd] section.

A dedicated system service, systemd-cron, handles the execution of timer units.

Timer units only exist in the system scope and are not available for users.

Each systemd timer unit controls a specific systemd service unit.

usermod

passwd

chattr

chage

chsh

The /etc/crontab file can specify a year field.

A normal crontab file must be installed with the crontab command.

A normal crontab file allows for environment variable substitution.

The /etc/crontab file has a user field for commands.

It is a plain text file containing a string such as Europe/Berlin

It is created and maintained by the NTP service based on the location of the system’s IP address.

It is a symlink to /sys/device/clock/ltime and always contains the current local time.

After changing this file, newtzconfig has to be run to make the changes effective.

It is either a symlink to or a copy of a timezone information file such as /usr/share/zoneinfo/Europe/Berlin.

Year

Minute

Username

Command

currency symbol

language

timezone

thousands separator

In the database file /etc/crontab.db which is shared by all users.

As individual per-user files within /var/spool/cron.

As individual per-user files in /etc/cron.user.d.

In the .crontab file in the user's home directory.

In the file /var/cron/user-crontab which is shared by all users.

It converts bitmap images from one format to another such as PNG to JPEG.

It verifies that the root directory tree complies to all conventions from the Filesystem Hierarchy Standard (FHS).

It displays additional meta information from icon files ending in .ico.

It changes the mode of an inode in the ext4 file system.

It converts files from one character encoding to another.

The list of users that belong to the group.

The home directory of the group.

The name of the group.

The description of the group.

The password of the group.

They are reserved for super user accounts.

They are reserved for the system admin accounts.

They are reserved for system accounts.

They are unused, aside from 0, because they are targets of exploits.

They are used to match with GIDs in grouping users.

The user issuing the command must be in the group script.

The script file must be found in the $PATH.

The script file must have the executable permission bit set.

The script must begin with a shebang-line (#!) that points to the correct interpreter.

The file system on which the script resides must be mounted with the option scripts.

SELECT (name, address) FROM contacts;

SELECT (name address) FROM contacts;

SELECT name, address FROM contacts;

SELECT name address FROM contacts;

It contains the welcome message that is displayed after login.

It contains security profiles defining which users are allowed to log in.

It contains environment variables that are set when a user logs in.

It contains default application profiles for users that run an application for the first time.

It is the process ID of the echo command.

It is the process ID of the current shell.

It is the exit value of the command executed immediately before echo.

It is the exit value of the echo command.

It is the process ID of the echo command.

It is the process ID of the current shell.

It is the process ID of the last command executed.

It is the process ID of the last command which has been placed in the background.

result: 3 4 5 6 2 1

result: 1 2 3 4 5 6

result: 6 5 4

result: 6 5 4 3 2 1

result: 3 2 1

A B

A B C

A C

B C

C B A

env

set

env -a

echo $ENV

hostname:displayname

hostname:displaynumber

hostname/displayname

hostname/displaynumber

hostname

It makes it difficult to uniquely identify a computer on the network.

It allows easy access to your X server by other users.

It logs sensitive information to syslog.

It makes your computer share network resources without any authentication.

It is a graphical DNS tool with known exploits.

To assist users who have difficulty holding down multiple keys at once

To prevent repeated input of a single character if the key is held down

To ignore brief keystrokes according to a specified time limit

To repeat the input of a single character

xkb

atkb

GOK

xOSK

When KDM starts

When a user's X session exits

When KDM crashes

When X is restarted

When X crashes

Start and prepare the desktop environment for the user.

Configure additional devices like new monitors or projectors when they are attached.

Handle the login of a user.

Lock the screen when the user was inactive for a configurable amount of time.

Create an X11 configuration file for the current graphic devices and monitors.

With IPv6, the TCP port numbers of most services have changed.

IPv6 no longer supports broadcast addresses.

IPv4 addresses can be used without any change with IPv6.

IPv6 no longer supports multicast addresses.

For IPv6, UDP and TCP have been replaced by the Rapid Transmission Protocol RTP.

Set a network interface active or inactive.

Specify the kernel module to be used with a network interface.

Allow regular users to change the network configuration of a network interface.

Change the netmask used on a network interface.

Specify which network services are available on a network interface.

It is used to configure where the C library looks for system information such as host names and user passwords.

It is used to configure network protocol port numbers such as for HTTP or SMTP.

It is used to configure LDAP authentication services for the local system.

It is used to configure which network services will be turned on during the next system boot.

2001:db8:3241::1

2001::db8:4581::1

2001:db8:0g41::1

2001%db8%9990%%1

2001.db8.819f..1

ps

netstat

nslookup

ifconfig

traceroute