LPI 010-160 Exam With Confidence Using Practice Dumps

The su command stands for substitute user or switch user. It allows you to run a shell or a command as another user, usually the superuser or root. To use the su command, you need to know the password of the target user. For example, if you want to switch to the root user, you can type su - and enter the root password. This will give you a root shell, where you can execute commands with administrative privileges. To exit the root shell, you can type exit or press Ctrl-D. The su command is not the default shell of the root account, nor can it only be used by the root user. It can be used by any user who knows the password of another user. The su command does not change the name of the main administrator account, which is always root on Linux systems. The su command also does not lock the root account in specific time frames, although there are other ways to do that, such as using the pam_time module. References:

• Linux Essentials - Linux Professional Institute (LPI), section 5.1.1
• LPI Linux Essentials Study Guide: Exam 010 v1.6, 3rd Edition, chapter 9, page 219.

 The correct command to extract the contents of the compressed archive file1.tar.gz is tar -xzf file1.tar.gz. This command uses the following options:

• -x means extract files from an archive.
• -z means filter the archive through gzip, which is a compression program that reduces the size of files.
• -f means use the following archive file name, which is file1.tar.gz in this case.

The other commands are incorrect for the following reasons:

• tar -czf file1.tar.gz creates a compressed archive file1.tar.gz from the files specified after the command, not extract it.
• ztar file1.tar.gz is not a valid command, as ztar is not a standard program or option for tar.
• tar --extract file1.tar.gz is missing the -z option to handle the gzip compression, and also the -f option to specify the file name.
• detar file1.tar.gz is not a valid command, as detar is not a standard program or option for tar.

References:

• Linux Essentials - Topic 106: The Linux Operating System, section 106.2 Use single shell commands and one line command sequences to perform basic tasks on the command line.
• LPI Linux Essentials Study Guide: Exam 010 v1.6, 3rd Edition, Chapter 5: Working with Files and Directories, section Compressing and Archiving Files.

 A typical shell script is a text file that contains a series of commands or instructions that can be executed by a shell interpreter. A shell script usually has the executable permission bit set, which means that it can be run as a program by the user or another program. A shell script also starts with the two character sequence #!, which is called a shebang or a hashbang. This sequence tells the operating system which shell interpreter to use to run the script. For example, #!/bin/bash indicates that the script should be run by the bash shell. References:

• Linux Essentials - Linux Professional Institute (LPI) 1
• Linux Essentials - Linux Professional Institute Certification Programs 2