Sysadmin tools
Converters, calculators and cheats for people who run servers.
tar Command Generator
Build, extract or list any tar archive by clicking, with every flag explained.
Runs in your browser
chmod Calculator
Visual Linux permissions calculator: octal, symbolic and the chmod command, both directions.
Runs in your browser
dd Command Generator
Build the dd command you can never quite remember, with every operand spelled out and a loud warning the moment your output is a real device.
Runs in your browser
Hyper-V Error Code Reference
Searchable Hyper-V error reference: type a code, message or symptom and get the cause plus the exact numbered fix. Runs in your browser.
Runs in your browser
Hyper-V PowerShell Generator
Tick a few boxes, get a Hyper-V PowerShell script you can paste and run. Create VMs, wire up virtual switches, handle checkpoints.
Runs in your browser
Linux Distro Command and Config Reference
Pick a distro and a topic, get the command, the config files, a walkthrough, the verify step, and the gotcha.
Runs in your browser
rsync Command Generator
Build rsync commands for local copies, backups and SSH transfers, with every flag explained.
Runs in your browser
systemd Service File Generator
Turn a command into a real systemd service: fill in ExecStart, Type, User and Restart, and copy a ready unit file plus the install commands.
Runs in your browser
VMware ESXi Error Code Reference
Searchable VMware vSphere and ESXi error reference with the real cause and a step-by-step fix for each one.
Runs in your browser
VMware PowerCLI Command Generator
Tick a few options and get PowerCLI that runs: VMs, snapshots, ESXi networking and esxcli, every cmdlet explained.
Runs in your browser
Reading in this category
CentOS to Rocky Linux 9 Migration Playbook 2026
CentOS to Rocky Linux 9 migration, end to end: the in-place ELevate route, the fresh-install route, the pre-flight inventory, and the breaks that fail silently.
The chmod and chown Cheatsheet, Decoded
A practical Linux chmod and chown cheatsheet: the Permission denied fix with chmod +x, why 755 and 644 keep showing up, chown for ownership, and recursing safely.
Choosing a Linux Distribution in 2026: Decision Guide
Choosing a Linux distribution in 2026 without the tribal noise: four inputs that decide (team skills, compliance, app stack, support) plus honest distro profiles.
Build a CTF Lab on Hyper-V: Full Walkthrough
Build a CTF lab on Hyper-V: three trust-segmented virtual switches, a Kali attacker, Metasploitable3 and a broken Windows 10, with pfSense in the middle for routing.
Fix: ESXi Host Not Responding in vCenter
ESXi host Not Responding in vCenter is almost always a dead management link, not a dead host. Restart hostd then vpxa, clear the log partition, check ports 902/443.
Hyper-V: The Hypervisor Is Not Running, Fix Guide
Fix Hyper-V 'the hypervisor is not running' by working the five gates in order: BIOS virtualization, the feature, hypervisorlaunchtype, conflicts, services.
Proxmox vs ESXi vs Hyper-V in 2026: Which to Run
Proxmox vs ESXi vs Hyper-V in 2026: honest cost, licensing, clustering, backup and containers after the Broadcom shakeup, plus which fits homelab or enterprise.
The rsync Cheatsheet: Mirror, Sync and Copy Over SSH
A practical Linux rsync cheatsheet: mirror with rsync -av, copy over ssh with -avz, mirror exactly with --delete, dry-run, resume, and the trailing slash gotcha.
Nagios on Hyper-V: Server Monitoring Setup Guide
Server monitoring with Nagios on a Hyper-V Ubuntu 24.04 VM: build Nagios 4.5 from source, aim HTTP, SSH, MySQL and disk probes, then wire mail and Telegram alerts.
SSH Command Cheatsheet: Connect, Keys, scp, Tunnels
A practical SSH command cheatsheet, most-used first: connect with ssh user@host, make an ed25519 key, push it with ssh-copy-id, copy files with scp, tunnel ports.
SSH Permission Denied (publickey): The Fix
Permission denied (publickey) is never mysterious once you read the handshake. The real causes in order, each with the exact command to confirm and fix it.
systemctl and journalctl Cheatsheet
A systemctl and journalctl cheatsheet: status to see if a service runs and why it died, restart, reload, enable --now, daemon-reload, and journalctl -u NAME -f.
The tar Command Cheatsheet: Create, Extract, List
A practical Linux tar cheatsheet: create a gzip archive with tar -czf, extract with tar -xzf (eXtract Ze File), list with tar -tzf, plus exclude and strip-components.
VMware ESXi PSOD: Diagnose and Recover the Host
VMware ESXi PSOD fix guide: read the purple screen, tell a bad driver from dying hardware, grab the coredump before you reboot, then recover the host.
VMware Workstation and Hyper-V on the Same PC (2026)
The VMware Device/Credential Guard not compatible error has two fixes: keep Hyper-V and upgrade VMware to Workstation 16+, or disable Hyper-V and VBS for VMware 15.
Migrer de CentOS vers Rocky Linux 9 en 2026
Migrer de CentOS vers Rocky Linux 9 de bout en bout : la voie in-place ELevate, la réinstallation propre, l'inventaire préalable et les casses silencieuses.
L'antisèche chmod et chown, décodée
Antisèche chmod et chown Linux : le remède au Permission denied avec chmod +x, pourquoi 755 et 644 reviennent sans arrêt, chown et récurser sans dégâts.
Choisir une distribution Linux en 2026 : le guide
Choisir une distribution Linux en 2026 : quatre critères qui décident vraiment (compétences, conformité, pile applicative, support), plus des profils honnêtes.
Monter un lab CTF sur Hyper-V : le guide complet
Monter un lab CTF sur Hyper-V : trois virtual switches segmentés par zone de confiance, un attaquant Kali, Metasploitable3 et un Windows 10 cassé, pfSense au centre.
Corriger un host ESXi Not Responding dans vCenter
Un host ESXi Not Responding dans vCenter est presque toujours un lien de management mort, pas un host mort. Redémarre hostd puis vpxa, vérifie les ports 902 et 443.
Hyper-V : the hypervisor is not running, le guide
Corriger Hyper-V the hypervisor is not running en passant les cinq barrières dans l'ordre : virtualisation BIOS, fonctionnalité, hypervisorlaunchtype et services.
Proxmox vs ESXi vs Hyper-V en 2026 : lequel choisir
Proxmox vs ESXi vs Hyper-V en 2026 : coût, licences, clustering, sauvegarde et conteneurs après le séisme Broadcom, et lequel convient au homelab ou à l'entreprise.
L'antisèche rsync : copier, synchroniser et miroir via ssh
Antisèche rsync Linux : copier à l'identique avec rsync -av, copier via ssh avec -avz, miroir exact avec --delete, simulation, reprise et le piège du slash final.
Nagios sur Hyper-V : guide du monitoring de serveurs
Monitoring de serveurs avec Nagios sur une VM Hyper-V Ubuntu 24.04 : compiler depuis les sources, sonder HTTP, SSH, MySQL et disque, alerter par mail et Telegram.
Antisèche des commandes SSH : clés, scp et tunnels
Une antisèche SSH, les commandes les plus utilisées en premier : se connecter avec ssh user@host, créer une clé ed25519, l'envoyer avec ssh-copy-id, copier avec scp.
SSH Permission denied (publickey) : le correctif
SSH Permission denied (publickey) n'est jamais mystérieux une fois la poignée de main lue. Les vraies causes dans l'ordre, chacune avec sa commande exacte.
Antisèche systemctl et journalctl
Antisèche systemctl et journalctl : status pour voir si un service tourne et pourquoi il est mort, restart, reload, enable --now et journalctl -u NAME -f.
Antisèche de la commande tar : créer, extraire, lister
Antisèche de la commande tar sous Linux : créer une archive gzip avec tar -czf, extraire avec tar -xzf, lister avec tar -tzf, plus exclude et strip-components.
VMware ESXi PSOD : diagnostiquer et récupérer le host
Guide PSOD VMware ESXi : lire l'écran violet, distinguer un driver fautif d'un hardware mourant, récupérer le core dump avant de rebooter, puis remonter le host.
VMware Workstation et Hyper-V sur le meme PC (2026)
L'erreur VMware Device/Credential Guard not compatible a deux correctifs : garder Hyper-V avec Workstation 16 et plus, ou couper Hyper-V et VBS pour VMware 15.