Linux(256 terms)
A full list of the Linux terms and explanations covered by ITBGM.
Use the search box below to filter by term name.
Each term links to a page with a more detailed, engineer-oriented explanation.
No terms match "
/etc/fstab File Systems ☆ A configuration file that defines which file systems to mount at boot.
/etc/hosts Network Configuration ☆ A configuration file for manually registering hostname-to-IP-address mappings.
/etc/passwd User Management ☆ A file recording basic information about user accounts.
/etc/shadow User Management ☆ A file recording users' encrypted password information.
/var/log Log Management ☆ The standard directory where various system and service logs are stored.
ACL Permissions ☆ A mechanism for setting permissions individually, beyond just the owner and group.
Alias Shell / Commands ☆ A feature that gives a frequently used command a shorter, alternative name.
AlmaLinux Distributions ☆ A distribution also built to be RHEL-compatible.
Alpine Linux Distributions ☆ A distribution known for being lightweight, also commonly used as a container base image.
Amazon Linux Distributions ☆ A distribution optimized for use on AWS.
AppArmor Permissions ☆ A mandatory access control mechanism that restricts what each program can access.
AppImage Package Management ☆ A portable app-distribution format that runs from a single file.
apt Package Management ☆ A package-management command used on Debian-based distributions.
Arch Linux Distributions ☆ A distribution that prioritizes simplicity, letting you build up what you need yourself.
auditctl Log Management ☆ A command for adding or changing the audit daemon auditd's monitoring rules while it's running.
auditd Log Management ☆ An auditing mechanism that records a system's operation history in detail.
awk Shell / Commands ☆ A command handy for processing and aggregating text column by column.
bash Shell / Commands ☆ A shell (a program that interprets commands) commonly used as the default on Linux.
Bind Mount File Systems ☆ A mount method that also makes a directory's contents visible at another location.
blkid Storage Management ☆ A command that displays the UUID and filesystem type of a block device.
Bonding Network Configuration ☆ A feature that bundles multiple network interfaces together for redundancy or higher throughput.
Bootloader Kernel ☆ A small program that, after power-on, loads and starts the OS kernel.
Bridge Network Configuration ☆ A feature that virtually joins multiple network interfaces into one segment.
Btrfs File Systems ☆ A relatively new file system with advanced features such as snapshots.
cat Shell / Commands ☆ A command that outputs a file's contents as-is.
cd Shell / Commands ☆ A command for changing the working directory.
CentOS Distributions ☆ A distribution that has been used as a Red Hat Enterprise Linux-compatible option.
cgroup systemd ☆ A mechanism that groups processes to limit and manage their CPU and memory usage.
chattr Permissions ☆ A command for setting special attributes on a file, such as making it unchangeable.
chgrp Permissions ☆ A command for changing a file's group ownership.
chmod Shell / Commands ☆ A command for changing the access permissions of a file or directory.
chown Shell / Commands ☆ A command for changing a file's owner or group.
chroot Container Platforms ☆ A mechanism that changes the root directory a process sees, isolating it.
Cockpit Development Environment ☆ A web-based management console from Red Hat that lets you check the status of a Linux server and operate it through a browser.
Command Substitution Shell / Commands ☆ A feature for embedding one command's output as part of another command.
Core Dump Process Management ☆ A file that captures a process's in-memory state at the moment it crashed.
cp Shell / Commands ☆ A command for copying files or directories.
cron Shell / Commands ☆ A mechanism for automatically running commands at a set time or interval.
Cross-Compilation Development Environment ☆ Building software for an environment different from the one doing the building.
curl Shell / Commands ☆ A command for sending and receiving data by specifying a URL.
cut Shell / Commands ☆ A command that extracts a specified column or character position from each line.
Daemon Process Management ☆ A process that runs continuously, resident in the background.
Debian Distributions ☆ An OS that prioritizes stability and forms the basis of many other distributions.
Dependency Resolution Package Management ☆ The process of automatically installing the other packages a package needs.
Device Driver Kernel ☆ Software the OS uses to control hardware.
df File Systems ☆ A command that shows disk usage per file system.
diff Shell / Commands ☆ A command that shows the difference between two files.
dig Network Configuration ☆ A command for making a DNS query and reviewing the result in detail.
disown Shell / Commands ☆ A shell command that detaches a running background job from the shell's job control.
dmesg Log Management ☆ A command that displays messages output by the kernel.
dnf Package Management ☆ A Red Hat-family package-management command used as the successor to yum.
dpkg Package Management ☆ The package format used on Debian-based systems, and its management command.
dracut Kernel ☆ A tool that generates the initramfs image used temporarily during boot.
du File Systems ☆ A command that shows the space used by a directory or file.
Dynamic Linking Development Environment ☆ A method that loads the needed libraries at run time.
eBPF Kernel ☆ A technology for safely extending the kernel without recompiling it, heavily used by monitoring and security tools.
Emacs Editors ☆ A leading text editor known for its extensibility, alongside Vim.
Environment Variable Shell / Commands ☆ A named setting that a shell or process can reference.
ext4 File Systems ☆ The standard file system widely used on Linux.
fdisk Storage Management ☆ A command for manipulating a disk's partitions.
Fedora Distributions ☆ A Red Hat-family distribution that's quick to adopt new technology.
File Descriptor File Systems ☆ A number identifying a file a process has open.
find Shell / Commands ☆ A command for searching for files or directories by condition.
firewalld Network Configuration ☆ A service that dynamically manages firewall rules using the concept of zones.
Flatpak Package Management ☆ A mechanism for distributing and running apps in a distribution-independent format.
free Shell / Commands ☆ A command that displays how much physical memory and swap a system is using.
fsck Storage Management ☆ A command for checking and repairing a file system's consistency.
gcc Development Environment ☆ A leading compiler for compiling languages such as C.
gdb Development Environment ☆ A debugger that lets you step through a program's behavior line by line.
getenforce / setenforce Permissions ☆ Commands for checking and changing SELinux's operating mode (Enforcing or Permissive).
getfacl Permissions ☆ A command for displaying the ACL set on a file.
grep Shell / Commands ☆ A command for searching for lines that match a string pattern.
groupadd User Management ☆ A command for creating a new group.
GRUB Kernel ☆ One of the bootloaders widely used on Linux.
gzip Shell / Commands ☆ A command for compressing and decompressing files.
Hard Link File Systems ☆ A mechanism that lets multiple file names reference the same underlying data.
Heredoc Shell / Commands ☆ A notation for passing multi-line text as a command's input.
history Shell / Commands ☆ A command that shows the history of previously run commands.
hostname Network Configuration ☆ A command for displaying and setting a system's hostname.
hostnamectl systemd ☆ A systemd command for viewing and setting the system's hostname.
htop Shell / Commands ☆ An interactive, improved version of the top command for viewing processes and resource usage.
id User Management ☆ A command that shows information such as user ID and group ID.
ifconfig Network Configuration ☆ A classic command for configuring and checking network interfaces.
initramfs Kernel ☆ A temporary root file system unpacked into memory early in the boot process.
initrd Kernel ☆ An initial RAM disk image used temporarily when the kernel boots.
inode File Systems ☆ A structure that holds a file's metadata -- name, permissions, location -- separately from its actual data.
inode Number File Systems ☆ A number that uniquely identifies each inode.
inotify Kernel ☆ A kernel mechanism for notifying applications of changes to files and directories.
insmod Kernel ☆ A command for manually loading a kernel module.
iostat Shell / Commands ☆ A command that displays CPU usage and disk I/O statistics.
ip a Network Configuration ☆ The current command for displaying network interface information.
ip route Network Configuration ☆ A command for displaying and modifying the routing table.
iptables Network Configuration ☆ A traditional firewall feature that performs packet filtering.
iSCSI Storage Management ☆ A technology for using storage as a block device over an IP network.
Job Control Shell / Commands ☆ A feature for controlling processes in the foreground or background.
journalctl systemd ☆ A command for viewing logs collected by systemd.
Journaling File Systems ☆ A file-system mechanism that records an update log to speed up recovery after a failure.
jq Shell / Commands ☆ A command-line tool for formatting, extracting, and transforming JSON data.
Kali Linux Distributions ☆ A Debian-based distribution that comes preloaded with tools for penetration testing and security assessment.
Kernel Kernel ☆ The core of the OS, bridging hardware and applications.
Kernel Module Kernel ☆ A unit of functionality that can be dynamically loaded into the kernel.
Kernel Panic Kernel ☆ A state where the kernel detects a fatal error and the system halts.
Kernel Parameters Kernel ☆ Settings for tuning kernel behavior at boot time or at runtime.
kill Process Management ☆ A command that sends a signal to a specified process, such as instructing it to terminate.
last Log Management ☆ A command that shows login history.
ldconfig Development Environment ☆ A command for updating the shared-library cache.
ldd Development Environment ☆ A command that shows the shared libraries an executable depends on.
less Shell / Commands ☆ A command for viewing a file's contents while scrolling.
Linux Capabilities Permissions ☆ A mechanism that splits the powerful privileges of root into fine-grained units that can be granted individually.
logger Log Management ☆ A command that sends log messages to syslog, for example from a shell script.
Logical Volume Storage Management ☆ In LVM, the unit carved out of a volume group for use.
logrotate Log Management ☆ A mechanism for periodically rotating, compressing, and deleting log files.
Loopback Device File Systems ☆ A virtual device that lets a file be treated like a disk.
ls Shell / Commands ☆ A command for listing a directory's contents.
lsattr Permissions ☆ A command that displays special attributes set on a file.
lsblk Storage Management ☆ A command that lists connected block devices (disks).
lsmod Kernel ☆ A command that lists the currently loaded kernel modules.
lsns Kernel ☆ A command that lists the Linux namespaces present on a system.
lsof Shell / Commands ☆ A command that lists currently open files and the processes using them.
LVM Storage Management ☆ A logical-volume-management feature that flexibly bundles multiple disks together.
LXC Container Platforms ☆ A container technology that uses Linux kernel features to achieve a lightweight virtual environment.
make Development Environment ☆ A tool for automating the steps to build source code.
Makefile Development Environment ☆ The file, read by make, that describes the build steps.
man Shell / Commands ☆ A command for displaying the manual to look up a command's usage and options.
mdadm Storage Management ☆ A command for building and managing software RAID.
mkdir Shell / Commands ☆ A command for creating a new directory.
mkfs Storage Management ☆ A command for creating a file system on a partition.
Mount File Systems ☆ Making storage usable as part of the directory tree.
Mount Point File Systems ☆ The directory a storage device is attached to.
mv Shell / Commands ☆ A command for moving or renaming files and directories.
namespace Container Platforms ☆ A mechanism that isolates the resources a process can see, underlying container technology.
nano Editors ☆ A text editor with simple operation, easy for beginners to use.
ncdu Storage Management ☆ A tool for interactively viewing disk usage in a text-based interface.
netcat Shell / Commands ☆ A general-purpose network utility for easily reading and writing TCP/UDP traffic.
netstat Network Configuration ☆ A classic command for displaying network connection status.
Network Interface Network Configuration ☆ A virtual or physical port serving as the OS's connection point to the network.
Network Namespace Network Configuration ☆ A mechanism for giving each process its own independent network environment.
NetworkManager Network Configuration ☆ A network-configuration management service used in desktop environments and elsewhere.
NFS Storage Management ☆ A mechanism for sharing a file system over a network.
nftables Network Configuration ☆ A packet-filtering mechanism that succeeds iptables.
nice Process Management ☆ A command for adjusting a process's CPU priority.
nmcli Network Configuration ☆ A tool for operating NetworkManager from the command line.
nohup Shell / Commands ☆ A command for keeping a process running even after you log out.
nslookup Network Configuration ☆ A long-standing command for resolving domain names.
objdump Development Environment ☆ A tool for analyzing and displaying an executable's internal structure.
OOM Killer Kernel ☆ A kernel mechanism that forcibly terminates a process to protect the system when memory runs out.
openssl Shell / Commands ☆ A command-line tool for encryption and certificate-related operations.
openSUSE Distributions ☆ A German-originated distribution based on SUSE.
overlayfs File Systems ☆ A file system that layers multiple directories to present them as one, commonly used in container technology.
pacman Package Management ☆ The package-management command used on Arch Linux.
Page Cache Kernel ☆ A kernel caching mechanism that keeps data read from disk in memory.
Partition Storage Management ☆ A division of a single disk into multiple regions.
passwd User Management ☆ A command for setting or changing a user's password.
perf Development Environment ☆ A profiling tool built into the Linux kernel for analyzing system-wide performance.
Permission Bits Permissions ☆ A bit string representing read, write, and execute permissions.
Physical Volume Storage Management ☆ In LVM, the unit corresponding to an actual disk or partition.
PID Process Management ☆ The identifying number assigned to each running process.
Pipe Shell / Commands ☆ A mechanism for connecting one command's output directly to another command's input.
Podman Container Platforms ☆ A container engine with no daemon, built for rootless execution by default.
proc File System Kernel ☆ A mechanism for viewing running-process and kernel information as virtual files.
Process Process Management ☆ A unit of a running program.
ps Process Management ☆ A command that lists running processes.
pstree Process Management ☆ A command that displays running processes as a tree, showing their parent-child relationships.
RAID Storage Management ☆ A technology that combines multiple disks to increase performance or fault tolerance.
Red Hat Enterprise Linux Distributions ☆ A leading commercial Linux offering with enterprise support.
Redirection Shell / Commands ☆ Switching a command's input or output to a file or similar destination.
renice Process Management ☆ A command that changes the priority (nice value) of an already-running process.
Repository Package Management ☆ The place where packages are distributed and stored.
resolv.conf Network Configuration ☆ A configuration file that specifies which DNS server to use.
rm Shell / Commands ☆ A command for deleting files or directories.
rmmod Kernel ☆ A command for removing a kernel module.
Rocky Linux Distributions ☆ A RHEL-compatible distribution created as a successor to CentOS.
Root Privileges Permissions ☆ The top-level administrator privilege that allows any operation on the system.
rpm Package Management ☆ The package format used on Red Hat-family systems, and its management command.
rsync Shell / Commands ☆ A command that efficiently transfers and syncs only the differences.
rsyslog Log Management ☆ A daemon that extends syslog for flexible log collection.
Samba Storage Management ☆ Software for sharing files and printers with Windows.
scp Shell / Commands ☆ A command for transferring files using the SSH mechanism.
sed Shell / Commands ☆ A command for text substitution and editing via stream processing.
SELinux Permissions ☆ A kernel security mechanism that applies mandatory access control to processes and files.
Service Unit systemd ☆ A type of unit for managing the startup and shutdown of a resident process.
setfacl Permissions ☆ A command for setting an ACL on a file.
SGID Permissions ☆ A setting that carries over group permissions when a file is executed or created.
Shebang Shell / Commands ☆ A notation written on a script's first line to specify which interpreter runs it.
Shell Script Shell / Commands ☆ A script that lists out commands to automate a sequence of tasks.
Signal Process Management ☆ A lightweight message delivered to a process as an interrupt.
snap Package Management ☆ A relatively new distribution format that packages a program together with its dependencies.
Snapshot Storage Management ☆ A feature for preserving a disk's state as of a particular point in time.
sort Shell / Commands ☆ A command for sorting text line by line.
ss Network Configuration ☆ A command for displaying socket state, the successor to netstat.
ssh Shell / Commands ☆ A command for connecting securely to a remote server.
stat Shell / Commands ☆ A command that displays detailed information about a file, such as size, timestamps, and permissions.
Static Linking Development Environment ☆ A method that embeds the needed libraries directly into an executable.
Sticky Bit Permissions ☆ A setting on a shared directory that prevents deleting files owned by others.
strace Development Environment ☆ A tool for tracing the system calls a program issues.
su User Management ☆ A command for switching to another user.
Subshell Shell / Commands ☆ A shell spawned as a child process, separate from the current one.
sudo Shell / Commands ☆ A command for temporarily running a command with administrator privileges.
sudoers Permissions ☆ The configuration file defining who can use what privileges via sudo.
SUID Permissions ☆ A setting that makes a program run with its file owner's privileges, rather than the running user's.
SUSE Linux Enterprise Server Distributions ☆ A commercially supported, enterprise-grade Linux distribution provided by SUSE.
Swap File Systems ☆ A mechanism that uses disk as virtual memory when physical memory runs short.
Symbolic Link File Systems ☆ A shortcut-like file that points to another file or directory elsewhere.
sysctl Kernel ☆ A command for checking and changing kernel parameters while the system is running.
syslog Log Management ☆ An umbrella term for mechanisms that collect and record system logs.
System Call Kernel ☆ The mechanism by which an application calls into kernel functionality.
systemctl systemd ☆ A command for starting, stopping, and checking systemd services.
systemd systemd ☆ A boot and service-management system used by many Linux distributions.
systemd-analyze systemd ☆ A command for analyzing how long the boot process took.
systemd-networkd systemd ☆ systemd's component for managing network configuration.
systemd-resolved systemd ☆ systemd's component responsible for name resolution.
tail Shell / Commands ☆ A command that displays the end of a file, commonly used for watching logs.
tar Shell / Commands ☆ A command for creating and extracting archives that bundle multiple files into one.
Target systemd ☆ A concept representing a system state, grouping together multiple units.
tcpdump Network Configuration ☆ A command for capturing and analyzing packets on the network.
tee Shell / Commands ☆ A command that sends standard input to both a file and standard output.
Thread Process Management ☆ A further-subdivided unit of execution within a process.
timedatectl systemd ☆ A systemd command for viewing and setting the system date, time, and timezone.
Timer Unit systemd ☆ A type of unit that triggers a task by time or interval, like cron.
tmpfs File Systems ☆ A file system built in memory -- fast, but wiped on reboot.
tmux Shell / Commands ☆ A terminal multiplexer that lets you create multiple sessions and split panes within a single terminal.
top Process Management ☆ A command that displays CPU and memory usage in real time.
touch Shell / Commands ☆ A command for creating an empty file or changing its modification time.
tr Shell / Commands ☆ A command for translating or deleting characters.
Ubuntu Distributions ☆ A popular Linux distribution that's also easy for beginners to use.
udev Kernel ☆ A mechanism that detects devices being connected or disconnected and dynamically manages device files.
ulimit Process Management ☆ A shell built-in command for setting and viewing the resource limits a single process can use.
umask Permissions ☆ A setting that specifies which bits to exclude from a newly created file's default permissions.
umount File Systems ☆ A command for detaching a mounted file system.
uname Kernel ☆ A command that displays system information such as the kernel version.
uniq Shell / Commands ☆ A command that collapses consecutive duplicate lines.
unit systemd ☆ The unit of work systemd manages, such as a service or a timer.
useradd User Management ☆ A command for creating a new user account.
userdel User Management ☆ A command for deleting a user account.
usermod User Management ☆ A command for changing an existing user account's settings.
vi Editors ☆ A long-standing Unix text editor notable for switching between modes.
Vim Editors ☆ A text editor that extends and enhances vi.
vmlinuz Kernel ☆ The file name referring to the Linux kernel itself, in compressed executable form.
vmstat Shell / Commands ☆ A command that displays virtual memory, process, and CPU usage statistics together.
Volume Group Storage Management ☆ In LVM, a unit that bundles multiple physical volumes together.
watch Shell / Commands ☆ A command that repeatedly runs a given command at a fixed interval and keeps displaying the result on screen.
Wayland Kernel ☆ A next-generation display server protocol intended to replace X11.
wc Shell / Commands ☆ A command for counting lines, words, bytes, and the like.
wget Shell / Commands ☆ A command for downloading a file from a specified URL.
which Shell / Commands ☆ A command for finding where a command's executable is located.
Wildcard Shell / Commands ☆ Symbols such as * and ? for specifying multiple file names at once.
WSL Development Environment ☆ A mechanism for running a Linux environment on Windows.
wtmp Log Management ☆ A file where login and logout history is recorded.
X11 Kernel ☆ The traditional display server protocol that has long been used in Linux desktop environments.
xargs Shell / Commands ☆ A command that passes standard input's contents as arguments to another command.
XFS File Systems ☆ A high-performance file system strong at handling large volumes of data.
yum Package Management ☆ A package-management command long used on Red Hat-family distributions.
ZFS File Systems ☆ A feature-rich file system strong at snapshots and data-protection capabilities.
Zombie Process Process Management ☆ A process whose work has finished but that its parent hasn't cleaned up yet.
zsh Shell / Commands ☆ A shell that serves as an alternative to bash, with enhanced completion and more.
zypper Package Management ☆ A package-management command used on openSUSE and similar distributions.
© 2026 ITBGM