Platform#
On Linux the operator administers the system, develops software and infrastructure, and commands, controls, and orchestrates operational assets. All of it builds on Linux fundamentals. Mastering the platform is foundational to CYBINT tradecraft.
This section reviews the components of the Linux platform, the boot process, kernel, shells, commands, filesystems, processes, memory, users, permissions, devices, packages, services, administration, standard I/O, and hardening.
Master the platform first; everything downstream rests on it.
The Linux distribution landscape. Family trees, package managers, init systems, release models.
Tools apt, dpkg, dnf, rpm, pacman.
The boot sequence. Firmware to bootloader to kernel to userspace.
Tools grub-mkconfig, update-grub, bootctl, efibootmgr, dracut.
The resident process at the bottom of every Linux box. The one thing on the host the operator cannot work around.
Tools uname, dmesg, sysctl, lsmod, modprobe.
The command-line interface. Where keystrokes become commands.
Tools bash, zsh, tmux, screen, history.
The GNU package shipping the basic file, text, and shell utilities every Linux box assumes are present.
Tools ls, cp, cat, cut, sort, head, tail.
One tree rooted at / where files, devices, kernel
objects, IPC endpoints, and remote mounts are all paths.
Tools ls, cp, mv, rm, find.
The operator’s smallest unit of observation on a live host. PID, parent, owning user, state.
Tools ps, top, htop, pgrep, pkill.
Virtual address spaces, paging, and the physical RAM behind them.
Tools free, vmstat, top, htop, pmap.
Identity is where every operation begins. UID, GID, and group membership.
Tools id, whoami, who, useradd, usermod.
The first lever on the platform. Every read, write, and execute passes through the permission stack.
Tools chmod, chown, chgrp, umask, getfacl.
Hardware through /dev, kernel state in /sys,
runtime info in /proc.
Tools lsblk, lspci, lsusb, lscpu, lshw.
Per-distribution package managers. Install, upgrade, query, remove.
Tools apt, dpkg, dnf, yum, rpm.
Long-running programs supervised by an init system. Daemons and the units that run them.
Tools systemctl, journalctl, systemd-analyze, loginctl, timedatectl.
The operator’s home turf. Configure, run, watch logs, keep the box honest between operations.
Tools sudo, su, journalctl, tail, less.
stdin, stdout, stderr. The composition glue
behind every pipeline.
Tools echo, cat, tee, xargs, printf.
Defensive posture on the platform. DAC, MAC, capabilities, sandboxes, audit.
Tools iptables, nftables, ufw, fail2ban, auditctl.