LPIC-1 101-500 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

initramfs

A temporary in-memory root filesystem loaded alongside the kernel. It contains the drivers and scripts needed to locate and mount the real root filesystem before handing control to init.

UEFI versus BIOS

UEFI boots .efi files from a FAT32 EFI System Partition on a GPT disk, while legacy BIOS executes boot code from the MBR of a traditionally partitioned disk.

modprobe command

Loads or unloads kernel modules by name, resolving dependencies recorded in modules.dep. The -r option removes a module together with its unused dependencies.

sysctl

Reads and writes kernel parameters exposed under /proc/sys. Persistent values belong in /etc/sysctl.conf or /etc/sysctl.d/, applied at boot or by sysctl -p.

udev

The device manager that receives kernel uevents and dynamically creates or removes nodes in /dev, applying rules found in /etc/udev/rules.d and /lib/udev/rules.d.

systemd target

A named group of units that replaces SysV runlevels: multi-user.target equals runlevel 3 and graphical.target equals 5, switched with systemctl isolate.

dpkg -S

Searches the installed Debian package database for the package that owns a given file path and prints the package name along with the matched file.

apt-get dist-upgrade

Performs a full upgrade that may install or remove additional packages to satisfy changed dependencies, unlike plain apt-get upgrade which never removes anything.

ldconfig

Rebuilds the shared library cache at /etc/ld.so.cache from directories listed in /etc/ld.so.conf and /etc/ld.so.conf.d, so binaries can locate libraries at runtime.

rpm -qf

Queries the RPM database to report which installed package provides a specified file, complementing rpm -ql which lists the files a package owns.

rpm2cpio

Converts an RPM package into a cpio archive written to standard output, so its payload can be listed or extracted with cpio without installing anything.

stderr redirection

File descriptor 2 is standard error. Writing 2> file sends errors to a file, 2>&1 merges errors into standard output, and &> file redirects both streams.

grep -v

Inverts matching so grep prints only the lines that do not contain the pattern. Related options are -i for case-insensitive matching and -n for line numbers.

uniq -c

Counts runs of consecutive identical lines in its input, which means the data must be sorted first, typically by piping sort output into uniq -c.

find -exec

Runs a command once per matched file, with {} replaced by the filename. Terminate with an escaped semicolon for per-file calls, or plus to batch arguments.

SIGTERM versus SIGKILL

SIGTERM (15) requests that a process terminate and can be caught or ignored. SIGKILL (9) cannot be caught or blocked and is enforced directly by the kernel.

tar -zcvf

Creates a gzip-compressed archive: c creates, v lists filenames while working, f names the archive file. Extraction uses -x and listing uses -t.

Command substitution

Replaces $(command) or backticks with the standard output of that command before the surrounding command executes, as in echo $(date) or ls $(pwd).

lsblk

Lists block devices in a tree showing disks, partitions, sizes, and mount points. It reads information from sysfs rather than inspecting each filesystem.

Major and minor numbers

Every device node carries a major number identifying its kernel driver and a minor number identifying the specific instance; mknod creates such nodes manually.

dd command

Copies raw data block by block from if= to of= using the block size given by bs=. It is used for disk images, backups, and wiping devices.

blkid

Prints the UUID, label, and filesystem type of block devices. These values are used to write stable /etc/fstab entries that survive device renaming.

partprobe

Asks the kernel to re-read a disk's partition table after it has been modified, so newly created or deleted partitions appear without rebooting the system.

fstab sixth field

The pass number controls boot-time fsck order: 0 skips checking, 1 is reserved for the root filesystem, and 2 is used for all other checked filesystems.

tune2fs

Adjusts ext2, ext3, and ext4 filesystem parameters in the superblock, such as maximum mount count (-c), check interval (-i), and volume label (-L), without re-creating it.

Hard link

A directory entry pointing to an existing inode, sharing the same data and inode number. It must remain on one filesystem and cannot target a directory.

swapon

Activates a swap area previously prepared with mkswap. swapon -s lists active swap spaces, and swapoff disables one so it can be repurposed.

noexec mount option

Prevents execution of binaries stored on that filesystem while still allowing reads and writes; it is commonly applied to /tmp and removable media.

df versus du

df reports free and used space for each mounted filesystem based on the superblock, while du sums the apparent sizes of files beneath a directory path.

Filesystem Hierarchy Standard

A specification defining the Linux directory layout and purpose, classifying paths as shareable or unshareable and as holding static or variable data.

/var/log

The standard location for variable log data generated by the system and its services, containing files such as messages and secure plus per-application subdirectories.

/usr/local

The hierarchy reserved for software installed by the system administrator outside the package manager, kept separate from distribution-managed files under the rest of /usr.