101-500 Exam Dumps - LPIC-1 Exam 101, Part 1 of 2, version 5.0

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 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 bg command is used to move and resume in the background the last stopped shell job. A stopped job is a process that has been suspended by using Ctrl+Z or the kill -STOP command. The bg command will resume the execution of the stopped job and allow it to run in the background, without blocking the current shell. The bg command can also take a job number as an argument, which can be obtained by using the jobs command. For example, if the last stopped job is 1+ Stopped sleep 500, then the following command will move and resume it in the background:

bg %1

The output will be:

1+ sleep 500 &

The fg command is used to move and resume in the foreground the last stopped or backgrounded job. The run and back commands are not valid commands in Linux. References:

[LPI Exam 101 Detailed Objectives], Topic 103: GNU and Unix Commands, Objective 103.5: Create, monitor and kill processes, Weight: 4, Key Knowledge Areas: Use of jobs, fg and bg commands.

Linux Commands: jobs, bg, and fg, Topic: The bg Command.

The command that is used to change options and positional parameters for a running Bash is set. The set command allows the user to modify the behavior of the shell by enabling or disabling various options, such as -x (trace mode), -e (exit on error), -u (treat unset variables as errors), and others. The set command can also be used to assign values to the positional parameters, which are the arguments passed to the shell or a shell script. The positional parameters are denoted by $1, $2, $3, and so on, up to $9. The special parameter 0referstothenameoftheshellortheshellscript.Thespecialparameter# refers to the number of positional parameters. The special parameter $@ refers to all the positional parameters as a list.

To change the positional parameters, the set command can be used with the – option, followed by the new arguments. For example, the following command will set the positional parameters to “a”, “b”, and “c”:

set – a b c

After this command, $1 will be “a”, $2 will be “b”, 3willbe"c",# will be 3, and $@ will be “a b c”. The – option signals the end of options and prevents any argument that starts with a - from being interpreted as an option. Alternatively, the set command can be used with the - option, followed by the new arguments. However, this will also disable the -x and -v options, if they were previously enabled. For example, the following command will set the positional parameters to “-a”, “-b”, and “-c”, and turn off the trace and verbose modes:

set - -a -b -c

The set command can also be used without any option or argument, in which case it will display the names and values of all shell variables and functions.

The other commands are not valid or relevant for changing options and positional parameters for a running Bash. The history command displays the history list of commands entered by the user. The bashconf command does not exist. The setsh command does not exist. The envsetup command does not exist.

The find command is used to search for files and directories that match certain criteria. The option -maxdepth can be used to restrict the command to searching down a particular number of subdirectories. The argument to -maxdepth is a positive integer that specifies the maximum depth of the directory tree to be searched. For example, -maxdepth 0 means only the current directory, -maxdepth 1 means the current directory and its direct subdirectories, and so on1. The option -maxdepth should be placed before any other expressions, as it affects the behavior of the whole command2. For example, to find all the files with the extension .txt in the current directory and its direct subdirectories, the command would be:

find . -maxdepth 1 -type f -name “*.txt”

The other options are not correct because:

A. -dirmax is not a valid find option.

C. -maxlevels is not a valid find option.

D. -depth is a valid find option, but it does not restrict the command to searching down a particular number of subdirectories. It only changes the order of the search, so that the files and directories are processed in depth-first order, meaning that the contents of a directory are processed before the directory itself1. References:

find(1) — Linux manual page

How to use find command to search for multiple extensions - Unix & Linux Stack Exchange

The tee command reads from standard input and writes to both standard output and one or more files1. Therefore, the command myapp | tee file1.log will send the output of the program myapp to both the terminal and the file file1.log. The other commands will either fail to write to both standard output and file, or write the wrong output. For example, the command cat < myapp | cat > file1.log will try to read the file myapp as input and write it to the file file1.log, but it will not display anything on the terminal. The command myapp 0>&1 | cat > file1.log will redirect the standard input of myapp to its standard output, and then pipe it to the file file1.log, but it will not display anything on the terminal. The command myapp | cat > file1.log will pipe the output of myapp to the file file1.log, but it will not display anything on the terminal. The command tee myapp file1.log will try to read from standard input and write to both the file myapp and the file file1.log, but it will not execute the program myapp. 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 command that displays the contents of a gzip compressed tar archive is tar ztf archive.tgz. This command uses the following options:

-z: Tells tar to read or write archives through gzip, allowing it to work on compressed files directly. -t: Lists the contents of an archive without extracting it. -f archive.tgz: Specifies the name of the archive file.

The output of this command will show the names of the files and directories stored in the archive, one per line. For example, if the archive contains three files named file1, file2, and file3, the output will be:

file1 file2 file3

The other commands are incorrect for the following reasons:

gzip archive.tgz | tar xvf -: This command will decompress the archive using gzip and pipe it to tar, which will extract the files to the current directory. The - option tells tar to read the archive from the standard input. This command does not display the contents of the archive, but rather extracts them.

gzip -d archive.tgz | tar tvf -: This command is similar to the previous one, except that it uses the -d option for gzip to decompress the archive instead of compressing it, and the -t option for tar to list the contents instead of extracting them. However, this command is redundant and inefficient, as tar can handle compressed archives directly with the -z option. Also, the -d option for gzip will delete the original archive file after decompression, which may not be desirable.

tar cf archive.tgz: This command will create a new archive named archive.tgz from the files and directories given as arguments. However, this command does not use the -z option, so the archive will not be compressed with gzip. Also, this command does not display the contents of the archive, but rather creates it.

The character that, added to the end of a command, runs that command in the background as a child process of the current shell is the ampersand symbol (&). This means that the command will not block the shell and the user can enter other commands while the background command is running. The background command will also not receive any input from the keyboard or the terminal. The shell will print the job number and the process ID of the background command, and the user can use the jobs command to list the status of all background jobs in the current shell session. To bring a background job to the foreground, the user can use the fg command with the job number or the process ID. To terminate a background job, the user can use the kill command with the process ID.

The other characters are not valid or relevant for running a command in the background. The exclamation mark (!) is used to access the command history or to negate a condition. The plus sign (+) is used for arithmetic operations or to append text. The percent sign (%) is used for arithmetic operations or to refer to a job number. The hash sign (#) is used for comments or to specify a hexadecimal number.