Free 101-400 sample questions

Correct answer: timeout

The timeout directive in GRUB Legacy configuration (/boot/grub/menu.lst) specifies how many seconds the boot menu is displayed before automatically booting the default entry. This allows users time to select alternate kernels or boot options. Other options like splash control boot screen appearance, while showmenu and hidemenu control menu visibility but not timing.

Correct answer: 10

When executing the nice command without parameters, it sets the nice level to 10, which lowers the process priority slightly. Nice values range from -20 (highest priority) to 19 (lowest priority), with 0 being the default. Only root can set negative nice values. The value 10 makes the process less competitive for CPU time.

Correct answers: echo “${PWD}”; pwd

Both pwd command and the PWD environment variable (accessed via echo "${PWD}") display the current working directory in Bash shell. The pwd command is a built-in that directly prints the current path, while PWD is automatically maintained by the shell to track directory changes. Other commands like printwd do not exist, and ${pwd} would be empty since it is not a predefined variable.

Both pwd command and the PWD environment variable (accessed via echo "${PWD}") display the current working directory in Bash shell. The pwd command is a built-in that directly prints the current path, while PWD is automatically maintained by the shell to track directory changes. Other commands like printwd do not exist, and ${pwd} would be empty since it is not a predefined variable.

Correct answer: The source and the target are on different filesystems.

Hard links cannot span different filesystems because they reference inodes, which are filesystem-specific. When source and target are on different filesystems, the ln command fails since the inode number would be meaningless across filesystem boundaries. Use symbolic links for cross-filesystem linking. File type, permissions, or existing links do not prevent hard link creation.

Correct answers: UUID; LABEL

Instead of device names like /dev/sdb1, Linux /etc/fstab supports UUID (Universally Unique Identifier) and LABEL identifiers for partition mounting. UUID provides persistent identification regardless of device name changes, while LABEL uses human-readable filesystem labels. Both methods are more reliable than device names since disk detection order can change between boots, potentially altering device assignments.

Instead of device names like /dev/sdb1, Linux /etc/fstab supports UUID (Universally Unique Identifier) and LABEL identifiers for partition mounting. UUID provides persistent identification regardless of device name changes, while LABEL uses human-readable filesystem labels. Both methods are more reliable than device names since disk detection order can change between boots, potentially altering device assignments.

Correct answer: By specifying the number right in front of a command such as 4l or 2yj.

In vi/vim, commands can be repeated by prefixing them with a number. For example, 4l moves cursor 4 positions right, 2yj copies 2 lines including current line, and 3dd deletes 3 lines. This numeric prefix applies to movement, editing, and copy commands. Vi does not have repetition settings or require line selection for command repetition.

Correct answers: /sbin/mke2fs -j /dev/sdb1; /sbin/mkfs -t ext3 /dev/sdb1

Both mke2fs -j /dev/sdb1 and mkfs -t ext3 /dev/sdb1 create ext3 filesystems. The mke2fs command with -j flag creates an ext3 filesystem by adding journaling to the base ext2 format. The mkfs command with -t ext3 directly specifies the ext3 filesystem type. Other options like mke3fs or mkfs.ext3 commands exist but were not listed as choices in this question.

Both mke2fs -j /dev/sdb1 and mkfs -t ext3 /dev/sdb1 create ext3 filesystems. The mke2fs command with -j flag creates an ext3 filesystem by adding journaling to the base ext2 format. The mkfs command with -t ext3 directly specifies the ext3 filesystem type. Other options like mke3fs or mkfs.ext3 commands exist but were not listed as choices in this question.

Correct answer: foo would be removed while bar would remain accessible.

When a hard link target is deleted, the file data remains accessible through other hard links because each link is an independent directory entry pointing to the same inode. The file is only truly deleted when the link count reaches zero. Therefore, deleting foo leaves bar fully functional with access to the original file data.

Correct answer: The command is run in background of the current shell.

The ampersand (&) character at the end of a command line runs the process in the background, allowing the shell to remain interactive while the command executes. The process continues running independently, and the shell immediately returns a prompt. Use jobs command to monitor background processes and fg to bring them to foreground.

Correct answer: Link count

Creating a hard link increases the link count of the target file, which tracks how many directory entries point to the same inode. This count is stored in the inode metadata and displayed by ls -l. File size, permissions, and timestamps remain unchanged. When the link count reaches zero, the file is deleted from the filesystem.