101-500 Exam Dumps - LPIC Level 1 Questions and Answers

When starting a program with the nice command without any additional parameters, the nice level is set to 10 for the resulting process. This means that the process will have a lower priority than the default value of 0, and will be more willing to yield CPU time to other processes. The nice command can also take an optional argument -n followed by a number, which specifies the increment or decrement of the nice value from the default value of 0. For example, the command:

nice -n 5 /usr/bin/prog

will start the /usr/bin/prog process with a nice value of 5, which means a lower priority than the default. Similarly, the command:

nice -n -5 /usr/bin/prog

will start the /usr/bin/prog process with a nice value of -5, which means a higher priority than the default. If the -n argument is omitted, the nice command will assume a default increment of 10. For example, the command:

nice /usr/bin/prog

will start the /usr/bin/prog process with a nice value of 10, which means a very low priority. Note that only the root user can start a process with a negative nice value, as this requires special privileges.

The rmdir command removes an empty directory. To remove a directory whose name contains a backslash, the backslash must be escaped with another backslash. Therefore, the correct command is rmdir ~/\dir. The other commands will either fail to find the directory or interpret the backslash as part of a path name. References:

[LPI Linux Essentials - 1.3 Basic Editing]

[LPI Linux Essentials - 1.4 I/O Redirection]

[LPI Linux Essentials - 1.5 Manage Simple Partitions and Filesystems]

 The find command is used to search for files and directories that match certain criteria. The -uid option specifies the numeric user ID of the owner of the file or directory, while the -user option specifies the name of the owner. The -print option prints the full file name of the matching file or directory to the standard output. Therefore, both find /tmp -uid root -print and find /tmp -user root -print will print all files and directories within the /tmp directory or its subdirectories which are also owned by the user root. The other options are either invalid or do not perform the desired task. The -path option matches the whole path name, not just the starting directory. The -print option is implied if no other action is specified, but it is good practice to include it for clarity. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.4 Use streams, pipes and redirects

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The correct way to set a Bash variable is to use the syntax variable=value without any spaces around the equal sign. The value can be enclosed in double quotes if it contains spaces or special characters, but it is not mandatory. Therefore, TEST="FOO" will set the Bash variable named TEST with the content FOO. The other options are either invalid or do not perform the desired task. The set command is used to set or unset shell options and positional parameters, not variables. The var command is not a valid Bash command. The TEST = "FOO" syntax will cause a syntax error because of the spaces around the equal sign. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.1 Work on the command line

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

 The output of the given command line is foo bar. The command line consists of three commands that are connected by pipes (|). A pipe is a symbol that redirects the standard output of one command to the standard input of another command. The echo command prints its argument to the standard output, which is foo bar in this case. The tee command reads from the standard input and writes to both the standard output and a file. The file name is given as an argument, which is bar in this case. The cat command reads from the standard input and writes to the standard output. Therefore, the command line does the following:

The echo command prints foo bar to the standard output, which is redirected to the standard input of the tee command by the first pipe.

The tee command reads foo bar from the standard input and writes it to both the standard output and the file bar. The standard output of the tee command is redirected to the standard input of the cat command by the second pipe.

The cat command reads foo bar from the standard input and writes it to the standard output, which is displayed on the terminal.

Hence, the output of the command line is foo bar. The other options are either incorrect or not applicable. The cat, tee bar and bar are not printed by any of the commands. The foo is only part of the output, not the whole output. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.4 Use streams, pipes and redirects

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The file command determines the type of a file by using a definition database file which contains information about all common file types. The database file is usually located at /usr/share/misc/magic or /usr/share/file/magic and can be customized by the user. The file command analyzes the content and structure of the file and compares it with the patterns in the database file to identify the file type. The file command can also check the file name extension, but it does not rely on it. The other options are either invalid or do not perform the desired task. The magic, pmagic and hash commands are not valid Linux commands. The type command is used to display information about command type, not file type. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.3 Perform basic file management

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The uptime and top commands can be used to determine how long the system has been running. The uptime command displays the current time, the system load, the number of users logged in, and the time since the system was last booted. The top command displays information about the processes running on the system, as well as the system load, the number of users logged in, and the time since the system was last booted. The other options are either invalid or do not perform the desired task. The up command is not a valid Linux command. The uname -u command displays the user ID of the current user, not the system uptime. The time –up command is not a valid syntax for the time command, which measures the execution time of a command, not the system uptime. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.2 Process management

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The commands init 1 and telinit 1 both bring a system running SysV init into a state in which it is safe to perform maintenance tasks. This state is also known as single-user mode or runlevel 1, where only the root user can log in and no network services are running. The command shutdown -R 1 now is incorrect, because it reboots the system instead of entering single-user mode. The command shutdown -single now is invalid, because the -single option does not exist for the shutdown command. The command runlevel 1 is also invalid, because runlevel is a command that displays the current and previous runlevels, not a command that changes the runlevel. References:

1: SysVinit - ArchWiki

2: Linux: How to write a System V init script to start, stop, and restart my own application or service - nixCraft

3: sysvinit - Gentoo wiki

The shutdown command is used to bring the system down in a safe and controlled way. It can take various options and arguments, such as the time of shutdown, the message to broadcast to users, the halt or reboot mode, etc. The option -r instructs the shutdown command to reboot the system after shutting down. The argument now means to shut down immediately. Therefore, shutdown -r now will reboot the system without delay. The telinit command is used to change the run level of the system. It takes a single argument that specifies the new run level. The run level 6 is reserved for rebooting the system. Therefore, telinit 6 will also reboot the system. The other options are either incorrect or irrelevant. shutdown -r “rebooting” will also reboot the system, but with a delay of one minute and a message to the users. telinit 0 will halt the system, not reboot it. shutdown -k now “rebooting” will only send a warning message to the users, but not actually shut down or reboot the system. References: LPI Linux Essentials - 1.101.2, LPI Linux Administrator - 101.3

The command that displays the contents of the Kernel Ring Buffer on the command line is dmesg12. The dmesg command is a Linux utility that displays kernel-related messages retrieved from the kernel ring buffer12. The ring buffer stores information about hardware, device driver initialization, and messages from kernel modules that take place during system startup12. The dmesg command is invaluable when troubleshooting hardware-related errors, warnings, and for diagnosing device failure2.

The dmesg command can be used with various options to control the output format, filter the messages by facility or level, clear the ring buffer, or follow the new messages in real time123. For example, the following command displays the last 10 messages from the kernel ring buffer:

$ dmesg | tail -10

The following command displays the messages from the kernel ring buffer in a human-readable format with colored output:

$ dmesg -H --color

The following command displays the messages from the kernel ring buffer that have the facility kern and the level emerg:

$ dmesg -f kern -l emerg

The following command clears the ring buffer:

$ dmesg --clear

The following command keeps dmesg running and waiting for new messages:

$ dmesg -w