hostname — Print Machine Name#

What it is#

hostname is a built-in Windows command that prints the NetBIOS / DNS hostname of the local machine to stdout. It takes no arguments and produces a single line of output — making it ideal for scripts that need to label output or branch on machine identity without shelling out to systeminfo or WMI.

Availability#

hostname ships as C:\Windows\System32\hostname.exe on every Windows version since NT 4.0. PowerShell equivalent: $env:COMPUTERNAME or [System.Net.Dns]::GetHostName().

hostname /?

Output:

Prints the name of the current host.

HOSTNAME

Basic usage#

Running hostname with no arguments prints the machine name and exits.

hostname

Output:

myhost

Capturing the hostname in a batch variable#

Assign the output of hostname to a variable with for /f so it can be reused in the same script.

for /f "delims=" %h in ('hostname') do set MACHINE=%h
echo %MACHINE%

Output:

myhost

In a batch file use double %%h:

@echo off
for /f "delims=" %%h in ('hostname') do set MACHINE=%%h
echo Running on %MACHINE%

Output:

Running on myhost

Using %COMPUTERNAME% as an alternative#

%COMPUTERNAME% is an environment variable that holds the same NetBIOS machine name as hostname. It is always available without a subprocess call, making it marginally faster in scripts.

echo %COMPUTERNAME%

Output:

MYHOST

rem %COMPUTERNAME% is uppercase; hostname output matches the stored name
hostname

Output:

myhost

Hostname in log file names#

Embedding the hostname in a file name makes log rotation across multiple machines trivial.

systeminfo > C:\Logs\sysinfo_%COMPUTERNAME%.txt
echo Written to sysinfo_%COMPUTERNAME%.txt

Output:

Written to sysinfo_MYHOST.txt

Checking hostname on a remote machine#

hostname only reports the local machine. To get a remote machine’s hostname by IP, use nslookup or ping -a.

ping -a 192.168.1.100 -n 1

Output:

Pinging myhost [192.168.1.100] with 32 bytes of data:
Reply from 192.168.1.100: bytes=32 time<1ms TTL=128

Three layers of “machine name” on Windows#

Windows actually tracks several distinct names for the same machine, and they don’t always agree. Understanding which command returns which name is the difference between a script that works and one that mysteriously targets the wrong host.

A machine renamed to BuildServer01 but still in the corp.example.com AD domain will return:

[System.Net.Dns]::GetHostName()
[System.Net.Dns]::GetHostEntry('').HostName

Output:

BuildServer01
BuildServer01.corp.example.com

PowerShell equivalents and richer queries#

PowerShell exposes the same name through several APIs. Each is preferable in different contexts — $env:COMPUTERNAME for speed, Get-CimInstance for cross-machine inventory, .NET [Dns] for FQDN logic.

$env:COMPUTERNAME

Output:

MYHOST

hostname

Output:

MYHOST

(Get-CimInstance Win32_ComputerSystem).Name

Output:

MYHOST

Get-CimInstance Win32_ComputerSystem | Select-Object Name, DNSHostName, Domain, Workgroup, PartOfDomain

Output:

Name        : MYHOST
DNSHostName : MYHOST
Domain      : corp.example.com
Workgroup   :
PartOfDomain: True

Get-ComputerInfo -Property CsName, CsDNSHostName, CsDomain, CsDomainRole

Output:

CsName        : MYHOST
CsDNSHostName : MYHOST
CsDomain      : corp.example.com
CsDomainRole  : MemberWorkstation

FQDN, domain, and DNS suffix#

The fully-qualified domain name is the hostname plus the connection-specific DNS suffix or the primary DNS suffix. hostname never returns the FQDN — use .NET [Dns]::GetHostEntry or read the suffix directly.

[System.Net.Dns]::GetHostEntry($env:COMPUTERNAME).HostName

Output:

MYHOST.corp.example.com

ipconfig /all | findstr /C:"Primary Dns Suffix" /C:"Host Name"

Output:

   Host Name . . . . . . . . . . . . : MYHOST
   Primary Dns Suffix  . . . . . . . : corp.example.com

Get-DnsClientGlobalSetting | Select-Object SuffixSearchList

Output:

SuffixSearchList
----------------
{corp.example.com, lab.example.com}

Renaming the machine#

Rename-Computer is the modern PowerShell way to change a Windows machine’s name; it updates both the NetBIOS name and the DNS host label. A reboot is required for the change to take full effect. The legacy netdom renamecomputer command does the same thing on Server SKUs.

Rename-Computer -NewName "BUILDSERVER02" -Force -Restart

Output:

WARNING: The changes will take effect after you restart the computer MYHOST.

For a domain-joined machine the operation requires domain admin credentials so AD can update the computer account at the same time:

Rename-Computer -NewName "BUILDSERVER02" -DomainCredential CORP\alicedev -Force -Restart

Output:

WARNING: The changes will take effect after you restart the computer MYHOST.

The legacy CMD equivalent on Server editions:

netdom renamecomputer MYHOST /NewName:BUILDSERVER02 /UserD:CORP\alicedev /PasswordD:* /Force /Reboot:0

Output:

The computer needs to be restarted in order to complete the operation.
The command completed successfully.

Reading machine name from the registry#

The persisted hostname lives in two registry keys; reading them works even when WMI is broken or the machine is offline (via offline registry mounting).

reg query "HKLM\SYSTEM\CurrentControlSet\Control\ComputerName\ComputerName" /v ComputerName
reg query "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v Hostname
reg query "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "NV Hostname"

Output:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ComputerName\ComputerName
    ComputerName    REG_SZ    MYHOST

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    Hostname    REG_SZ    MYHOST

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    NV Hostname    REG_SZ    MYHOST

If those three values disagree, the machine is mid-rename and waiting for a reboot.

Common pitfalls#

1. hostname vs %COMPUTERNAME% — both return the machine name but hostname invokes a subprocess; prefer %COMPUTERNAME% in tight loops.
2. Case difference — hostname.exe returns the name as stored (often lower-case or mixed); %COMPUTERNAME% is always upper-case. Normalise with for /f "usebackq" %%h in (hostname) do ... when case matters.
3. No remote querying — hostname has no /S flag; use nslookup <IP>, ping -a <IP>, or WMI for remote lookups.
4. FQDN vs short name — hostname returns only the short (NetBIOS) name. For the fully-qualified domain name use PowerShell: [System.Net.Dns]::GetHostEntry('').HostName.
5. 15-character NetBIOS cap — NetBIOS names are limited to 15 characters; longer DNS host labels work locally but break legacy SMB/RPC name resolution. Tools that read %COMPUTERNAME% silently truncate.
6. Stale %COMPUTERNAME% after rename — the env var is set at user logon; after Rename-Computer it stays at the old name until the next sign-in even though hostname.exe already returns the new one.
7. Pending rename hides the new name — after Rename-Computer (without -Restart) hostname may still report the old name until reboot; check HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\NV Hostname for the queued value.
8. Sysprepped images — a machine cloned without sysprep keeps the source machine’s name and SID; hostname reports the duplicated name, AD will refuse the second join.
9. _CLUSTER_NETWORK_NAME_ overrides hostname output — Microsoft Learn documents that when this environment variable is defined (Windows clustering sets it inside resource scripts), hostname.exe prints the variable’s value instead of the real machine name. Useful for cluster-aware scripts; surprising in non-cluster contexts where a stray set leaks the value.
10. TCP/IP must be installed — hostname.exe is only available when the Internet Protocol (TCP/IP) component is bound to a network adapter; on stripped-down container images that omit TCP/IP it returns an error. %COMPUTERNAME% works regardless.
11. Any argument other than /? is an error — hostname foo doesn’t print anything new; it just prints an error message and exits with errorlevel 1. There is no -s, -f, -d, or -i like the Unix tool.

Real-world recipes#

Label a multi-machine inventory script#

@echo off
for /f "delims=" %%h in ('hostname') do set H=%%h
echo %H%,%DATE%,%TIME% >> C:\Audit\inventory.csv
systeminfo /FO CSV /NH >> C:\Audit\inventory.csv
echo %H% logged.

Output:

MYHOST logged.

Conditional logic based on machine name#

@echo off
for /f "delims=" %%h in ('hostname') do set H=%%h
if /i "%H%"=="buildserver" (
    echo Running build tasks
) else (
    echo Skipping — not the build server
)

Output:

Skipping — not the build server

Include hostname in a support-ticket dump#

echo === Machine: %COMPUTERNAME% === > support.txt
echo === Date: %DATE% %TIME% === >> support.txt
ipconfig /all >> support.txt
echo Done. Send support.txt to the helpdesk.

Output:

Done. Send support.txt to the helpdesk.

Roll a fleet-wide hostname inventory with PowerShell remoting#

Invoke-Command runs the same script block against many machines in parallel — far better than a serial for loop. Combine with Get-CimInstance for richer detail than hostname alone.

$targets = 'web01', 'web02', 'db01', 'build01'
Invoke-Command -ComputerName $targets -ScriptBlock {
    [PSCustomObject]@{
        NetBIOS = $env:COMPUTERNAME
        DnsHost = [System.Net.Dns]::GetHostName()
        FQDN    = [System.Net.Dns]::GetHostEntry('').HostName
        Domain  = (Get-CimInstance Win32_ComputerSystem).Domain
    }
} | Format-Table -AutoSize

Output:

NetBIOS  DnsHost  FQDN                          Domain
-------  -------  ----                          ------
WEB01    web01    web01.corp.example.com        corp.example.com
WEB02    web02    web02.corp.example.com        corp.example.com
DB01     db01     db01.corp.example.com         corp.example.com
BUILD01  build01  build01.corp.example.com      corp.example.com

Cross-reference DNS records against actual hostnames#

If hostname on 10.0.0.5 reports something different from the PTR record, DNS is stale or the machine was renamed without ipconfig /registerdns.

$ip = '10.0.0.5'
$ptr = (Resolve-DnsName $ip -ErrorAction SilentlyContinue).NameHost
$real = Invoke-Command -ComputerName $ip -ScriptBlock { hostname }
"PTR: $ptr  ACTUAL: $real"

Output:

PTR: oldname.corp.example.com  ACTUAL: BUILDSERVER01

Rename a machine and join it to a domain in one step#

Add-Computer accepts a -NewName parameter — useful when provisioning a freshly imaged box. The reboot completes both operations atomically.

$cred = Get-Credential CORP\domainadmin
Add-Computer -DomainName corp.example.com -NewName 'WEB-NEW01' -Credential $cred -Restart

Output:

WARNING: The changes will take effect after you restart the computer.

Branch a deployment script on machine role suffix#

A common provisioning pattern bakes role into the hostname (WEB01, DB01, BUILD01). Branch logic on the first three characters of %COMPUTERNAME%.

@echo off
set ROLE=%COMPUTERNAME:~0,3%
if /i "%ROLE%"=="WEB" (
    echo Installing web role
) else if /i "%ROLE%"=="DB-" (
    echo Installing database role
) else (
    echo Unknown role for %COMPUTERNAME%
)

Output:

Installing web role

Related references#

Sources#

• hostname — Microsoft Learn