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Practical tools and guides for system administrators

Command builders, cheat sheets and field-tested guides for the work you actually do on Windows Server, Active Directory and vSphere.

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26cheat sheets
111guides
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Windows command linerobocopy · reg · schtasks · sfc PowerShellGet-WinEvent · Get-Counter · Base64 Active Directorynltest · dcdiag · DFS · Kerberos VMwareesxcli · PowerCLI · Invoke-VMScript Networking and DNSipconfig · netstat · tracert · nslookup Storage and backupvssadmin · wbadmin · diskpart · mklink Security and accessicacls · runas · certutil · OpenSSL Linuxssh · disks · systemctl · vi
Tools

Run it in the browser, copy the command

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ROBOCOPY command builderBuild a /MIR copy with retries, logging and exclusions without guessing switches.Open tool PowerCLI command builderInventory, snapshot and VM power one-liners for vSphere, ready to paste.Open tool Windows Event Log Analyzer AIPaste an event, get the likely cause and the next command to run.Open tool IP subnet calculatorNetwork, broadcast, host range and mask for any CIDR block.Open tool DNS lookupA, MX, TXT, CNAME and NS records for any domain in one query.Open tool Port checkerIs the TCP port open from the internet, or is the firewall in the way.Open tool nltest command builderDomain controller discovery and secure channel checks, switch by switch.Open tool Windows 11 registry tweaksReady-to-import .reg files for the Windows 11 settings admins change most.Open tool
Cheat sheets

One page per tool, printable

Free PDF packFive cheat sheets, one PDFSubnets, PowerShell, Linux, HTTP codes and ESXi. Free, by email.Get the pack PS> Get-HelpPowerShell commandsPowerShell robocopy /MIR /LRobocopy: flags, filters and exit codesWindows command line Event ID 4625Windows Event IDsWindows /24 = 255.255.255.0Subnet masksNetworking esxcli system version getESXi command lineVMware $ ls -laLinux commandsLinux icacls D:\Share /TNTFS permissions and icaclsSecurity and access openssl x509 -textOpenSSLSecurity and access All cheat sheets
Latest guides

New on the site

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PowerShellPS> Get-FileHashSep 30, 2026 · GuideGet-FileHash: the comparison that reports a good file as badThe two commands in the title answer the same question from opposite ends of the machine. Get-FileHash is a PowerShell cmdlet: it reads a...Storage and backupC:\> fsutil 8dot3nameSep 29, 2026 · Guidefsutil 8dot3name: the files strip silently skipsEvery file created on an NTFS volume with 8.3 name creation left on gets two names, not one. There is the long name a...Security and accessC:\> remove RDS key packSep 28, 2026 · GuideRemove a duplicate RDS key pack without rebuilding the databaseRD Licensing Manager has no Delete. Remove one redundant RDS CAL key pack by its KeyPackId with PowerShell and leave the rest of the...Active DirectoryC:\> dfsrdiagSep 28, 2026 · Guidedfsrdiag backlog: why the count is not in the outputdfsrdiag is the operational and diagnostic command line tool that ships with DFS Replication, and its dfsrdiag backlog subcommand answers one question: how many...Networking and DNSC:\> SPFSep 27, 2026 · GuideSPF, DKIM and DMARC: why a TXT query finds only SPFThree DNS records decide whether mail claiming to come from a domain is accepted, and all three are TXT records. That is where the...Networking and DNSC:\> New-NetFirewallRuleSep 26, 2026 · GuideNew-NetFirewallRule: why Get-NetFirewallRule shows no portsNew-NetFirewallRule creates an inbound or outbound Windows Firewall rule and attaches it to a policy store, which is the scripted replacement for clicking through...
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About

Written from real infrastructure work

Hi, I’m Zaur, a system administrator working mainly with Windows infrastructure, VMware, AWS, automation and troubleshooting. This website brings together practical tools, cheat sheets and technical guides based on real-world infrastructure work. The goal is simple: help system administrators solve everyday tasks faster.

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