102-500 Deutsch 無料問題集「Lpi LPIC-1 Exam 102, Part 2 of 2, version 5.0 (102-500 Deutsch Version)」
Welche Umgebungsvariable wird bei X11-Weiterleitung in ssh automatisch in der Remote-Host-Shell festgelegt, wenn die X11-Weiterleitung nicht aktiviert ist? (Geben Sie nur die Umgebungsvariable ohne zusätzliche Befehle oder Werte an.)
正解：
ISPLAYDISPLAY
Explanation:
With X11 forwarding in ssh, the environment variable that is automatically set in the remote host shell is DISPLAY. This variable specifies the name of the X display to which X11 clients should connect. When X11 forwarding is enabled, the ssh server sets the DISPLAY variable to a value like localhost:10.0, which means that the X11 clients will connect to a proxy X11 display on the remote host. The proxy display will then forward the X11 protocol over ssh to the X server on the local host. This way, the X11 clients can display their graphical output on the local host, even though they are running on the remote host. If X11 forwarding is not enabled, the DISPLAY variable is not set by the ssh server, and the X11 clients will not be able to connect to any X display unless the user manually sets the DISPLAY variable to a valid value. However, this may not work if the X server on the local host does not allow remote connections or if there are firewall rules that block the X11 traffic.
Reference:
3: Built-in SSH X11 forwarding in PowerShell or Windows Command Prompt - X410
4: Understanding X11 Forwarding through SSH - start to finish steps
1: Why use ssh X11 forwarding with LSF; How to use ssh X11 forwarding - IBM
Explanation:
With X11 forwarding in ssh, the environment variable that is automatically set in the remote host shell is DISPLAY. This variable specifies the name of the X display to which X11 clients should connect. When X11 forwarding is enabled, the ssh server sets the DISPLAY variable to a value like localhost:10.0, which means that the X11 clients will connect to a proxy X11 display on the remote host. The proxy display will then forward the X11 protocol over ssh to the X server on the local host. This way, the X11 clients can display their graphical output on the local host, even though they are running on the remote host. If X11 forwarding is not enabled, the DISPLAY variable is not set by the ssh server, and the X11 clients will not be able to connect to any X display unless the user manually sets the DISPLAY variable to a valid value. However, this may not work if the X server on the local host does not allow remote connections or if there are firewall rules that block the X11 traffic.
Reference:
3: Built-in SSH X11 forwarding in PowerShell or Windows Command Prompt - X410
4: Understanding X11 Forwarding through SSH - start to finish steps
1: Why use ssh X11 forwarding with LSF; How to use ssh X11 forwarding - IBM
Mit welchem Befehl wird die Hardwareuhr mit der Systemuhr synchronisiert? (Geben Sie NUR den Befehl ohne Pfad oder Parameter an.)
正解：
hwclocksbinhwclockusrsbinhwclock
Explanation:
The command that is used to sync the hardware clock to the system clock is:
hwclock --systohc
This command copies the current system time to the hardware clock, which runs even when the system is shut down. It is equivalent to the command hwclock -w12. The hardware clock is also called the BIOS clock or the RTC (Real Time Clock)3.
Explanation:
The command that is used to sync the hardware clock to the system clock is:
hwclock --systohc
This command copies the current system time to the hardware clock, which runs even when the system is shut down. It is equivalent to the command hwclock -w12. The hardware clock is also called the BIOS clock or the RTC (Real Time Clock)3.
Mit welchem Befehl können Sie die Eigenschaften eines bestimmten Fensters in X untersuchen, indem Sie auf dieses Fenster klicken? (Geben Sie NUR den Befehl ohne Pfad oder Parameter an.)
正解：
usrbinxwininfoxwininfo
Explanation:
The command that can be used to investigate the properties for a particular window in X by clicking that window is xwininfo. xwininfo is a command-line tool that provides information about X windows. When executed, it opens a small window and waits for the user to select a window by clicking on it. Then, it displays various characteristics about the window in question, such as its geometry, position, size, depth, class, name, id, and more. xwininfo is part of the X Window System, which is a graphical user interface system for Unix-like operating systems. xwininfo can be useful for debugging, testing, or scripting purposes. Reference: https://bing.com/search?q=command+to+investigate+properties+of+a+window+in+X
https://www.exam-answer.com/linux-foundation-certified-system-administrator-lfcs-simulation-investigate-window-properties
Explanation:
The command that can be used to investigate the properties for a particular window in X by clicking that window is xwininfo. xwininfo is a command-line tool that provides information about X windows. When executed, it opens a small window and waits for the user to select a window by clicking on it. Then, it displays various characteristics about the window in question, such as its geometry, position, size, depth, class, name, id, and more. xwininfo is part of the X Window System, which is a graphical user interface system for Unix-like operating systems. xwininfo can be useful for debugging, testing, or scripting purposes. Reference: https://bing.com/search?q=command+to+investigate+properties+of+a+window+in+X
https://www.exam-answer.com/linux-foundation-certified-system-administrator-lfcs-simulation-investigate-window-properties
Mit welchem Befehl wird der Hostname des lokalen Systems festgelegt? (Geben Sie NUR den Befehl ohne Pfad oder Parameter an.)
正解：
hostname
Explanation:
The hostname command is used to set the hostname of the local system. The hostname command can take a single argument, which is the new hostname to be assigned to the system. For example, to set the hostname to linux, one can run:
hostname linux
The hostname command can also be used without any arguments to display the current hostname of the system. For example, to show the current hostname, one can run:
hostname
The hostname command only changes the hostname temporarily, meaning that the original hostname will be restored after a reboot. To change the hostname permanently, one has to edit the configuration files that store the hostname information, such as /etc/hostname, /etc/hosts, /etc/sysconfig/network, etc. The exact files and commands may vary depending on the Linux distribution and the system initialization process. For more details, please refer to the web search results1 or the question answering results2. Reference:
Explanation:
The hostname command is used to set the hostname of the local system. The hostname command can take a single argument, which is the new hostname to be assigned to the system. For example, to set the hostname to linux, one can run:
hostname linux
The hostname command can also be used without any arguments to display the current hostname of the system. For example, to show the current hostname, one can run:
hostname
The hostname command only changes the hostname temporarily, meaning that the original hostname will be restored after a reboot. To change the hostname permanently, one has to edit the configuration files that store the hostname information, such as /etc/hostname, /etc/hosts, /etc/sysconfig/network, etc. The exact files and commands may vary depending on the Linux distribution and the system initialization process. For more details, please refer to the web search results1 or the question answering results2. Reference:
Was ist der unprivilegierte TCP-Port mit der niedrigsten Nummer? (Geben Sie die Nummer nur in Ziffern an.)
正解：
1024
Explanation:
The lowest numbered unprivileged TCP port is 1024. A port number is a 16-bit unsigned integer, thus ranging from 0 to 65535. The port numbers in the range from 0 to 1023 are the well-known ports or system ports. They are used by system processes that provide widely used types of network services. On Unix-like operating systems, a process must execute with superuser privileges to be able to bind a network socket to an IP address using one of the well-known ports. Therefore, the lowest numbered port that can be used by a normal user without root access is 1024, which is the first unprivileged port123 Reference:
1: How to bind to port number less than 1024 with non root access?
2: lowest numbered unprivileged TCP port - Bing
3: List of TCP and UDP port numbers - Wikipedia
4: Privileged Ports - World Wide Web Consortium (W3C)
5: What is the lowest TCP port number? - TeachersCollegesj
Explanation:
The lowest numbered unprivileged TCP port is 1024. A port number is a 16-bit unsigned integer, thus ranging from 0 to 65535. The port numbers in the range from 0 to 1023 are the well-known ports or system ports. They are used by system processes that provide widely used types of network services. On Unix-like operating systems, a process must execute with superuser privileges to be able to bind a network socket to an IP address using one of the well-known ports. Therefore, the lowest numbered port that can be used by a normal user without root access is 1024, which is the first unprivileged port123 Reference:
1: How to bind to port number less than 1024 with non root access?
2: lowest numbered unprivileged TCP port - Bing
3: List of TCP and UDP port numbers - Wikipedia
4: Privileged Ports - World Wide Web Consortium (W3C)
5: What is the lowest TCP port number? - TeachersCollegesj