See also: SetX.exe
C:\>SET /?
Displays, sets, or removes cmd.exe environment variables.
SET [variable=[string]]
variable Specifies the environment-variable name.
string Specifies a series of characters to assign to the variable.
Type SET without parameters to display the current environment variables.
If Command Extensions are enabled SET changes as follows:
SET command invoked with just a variable name, no equal sign or value
will display the value of all variables whose prefix matches the name
given to the SET command. For example:
SET P
would display all variables that begin with the letter 'P'
SET command will set the ERRORLEVEL to 1 if the variable name is not
found in the current environment.
SET command will not allow an equal sign to be part of the name of
a variable.
Two new switches have been added to the SET command:
SET /A expression
SET /P variable=[promptString]
The /A switch specifies that the string to the right of the equal sign
is a numerical expression that is evaluated. The expression evaluator
is pretty simple and supports the following operations, in decreasing
order of precedence:
() - grouping
! ~ - - unary operators
* / % - arithmetic operators
+ - - arithmetic operators
<< >> - logical shift
& - bitwise and
^ - bitwise exclusive or
| - bitwise or
= *= /= %= += -= - assignment
&= ^= |= <<= >>=
, - expression separator
If you use any of the logical or modulus operators, you will need to enclose the expression string in quotes. Any non-numeric strings in the expression are treated as environment variable names whose values are converted to numbers before using them. If an environment variable name is specified but is not defined in the current environment, then a value of zero is used. This allows you to do arithmetic with environment
variable values without having to type all those % signs to get their
values. If SET /A is executed from the command line outside of a command script, then it displays the final value of the expression. The assignment operator requires an environment variable name to the left of the assignment operator. Numeric values are decimal numbers, unless prefixed by 0x for hexadecimal numbers, and 0 for octal numbers. So 0x12 is the same as 18 is the same as 022. Please note that the octal notation can be confusing: 08 and 09 are not valid numbers because 8 and 9 are not valid octal digits.
The /P switch allows you to set the value of a variable to a line of input entered by the user. Displays the specified promptString before reading the line of input. The promptString can be empty.
Environment variable substitution has been enhanced as follows:
%PATH:str1=str2%
would expand the PATH environment variable, substituting each occurrence of "str1" in the expanded result with "str2". "str2" can be the empty string to effectively delete all occurrences of "str1" from the expanded output. "str1" can begin with an asterisk, in which case it will match everything from the beginning of the expanded output to the first occurrence of the remaining portion of str1.
May also specify substrings for an expansion.
%PATH:~10,5%
would expand the PATH environment variable, and then use only the 5 characters that begin at the 11th (offset 10) character of the expanded result. If the length is not specified, then it defaults to the remainder of the variable value. If either number (offset or length) is negative, then the number used is the length of the environment variable value added to the offset or length specified.
%PATH:~-10%
would extract the last 10 characters of the PATH variable.
%PATH:~0,-2%
would extract all but the last 2 characters of the PATH variable.
Finally, support for delayed environment variable expansion has been added. This support is always disabled by default, but may be enabled/disabled via the /V command line switch to CMD.EXE. See 'CMD /?'
Delayed environment variable expansion is useful for getting around the limitations of the current expansion which happens when a line of text is read, not when it is executed. The following example demonstrates the problem with immediate variable expansion:
set VAR=before
if "%VAR%" == "before" (
set VAR=after
if "%VAR%" == "after" @echo If you see this, it worked
)
would never display the message, since the %VAR% in BOTH IF statements is substituted when the first IF statement is read, since it logically includes the body of the IF, which is a compound statement. So the IF inside the compound statement is really comparing "before" with "after" which will never be equal. Similarly, the following example will not work as expected:
set LIST=
for %i in (*) do set LIST=%LIST% %i
echo %LIST%
in that it will NOT build up a list of files in the current directory, but instead will just set the LIST variable to the last file found. Again, this is because the %LIST% is expanded just once when the FOR statement is read, and at that time the LIST variable is empty.
So the actual FOR loop we are executing is:
for %i in (*) do set LIST= %i
which just keeps setting LIST to the last file found.
Delayed environment variable expansion allows you to use a different
character (the exclamation mark) to expand environment variables at
execution time. If delayed variable expansion is enabled, the above
examples could be written as follows to work as intended:
set VAR=before
if "%VAR%" == "before" (
set VAR=after
if "!VAR!" == "after" @echo If you see this, it worked
)
set LIST=
for %i in (*) do set LIST=!LIST! %i
echo %LIST%
If Command Extensions are enabled, then there are several dynamic environment variables that can be expanded but which don't show up in the list of variables displayed by SET. These variable values are computed dynamically each time the value of the variable is expanded. If the user explicitly defines a variable with one of these names, then that definition will override the dynamic one described below:
%CD% - expands to the current directory string.
%DATE% - expands to current date using same format as DATE command.
%TIME% - expands to current time using same format as TIME command.
%RANDOM% - expands to a random decimal number between 0 and 32767.
%ERRORLEVEL% - expands to the current ERRORLEVEL value
%CMDEXTVERSION% - expands to the current Command Processor Extensions
version number.
%CMDCMDLINE% - expands to the original command line that invoked the Command Processor.
%HIGHESTNUMANODENUMBER% - expands to the highest NUMA node number on this machine.
ALLUSERSPROFILE=C:\ProgramData
APPDATA=C:\Users\<UserName>\AppData\Roaming
CommonProgramFiles=C:\Program Files\Common Files
CommonProgramFiles(x86)=C:\Program Files (x86)\Common Files
CommonProgramW6432=C:\Program Files\Common Files
COMPUTERNAME=ITTECH
ComSpec=C:\Windows\system32\cmd.exe
FP_NO_HOST_CHECK=NO
HOMEDRIVE=M:
HOMEPATH=\\
HOMESHARE=\\Server\<UserName>
LOCALAPPDATA=C:\Users\<UserName>\AppData\Local
LOGONSERVER=\\SERVER
NUMBER_OF_PROCESSORS=4
OS=Windows_NT
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
PROCESSOR_ARCHITECTURE=AMD64
PROCESSOR_IDENTIFIER=Intel64 Family 6 Model 42 Stepping 7, GenuineIntel
PROCESSOR_LEVEL=6
PROCESSOR_REVISION=2a07
ProgramData=C:\ProgramData
ProgramFiles=C:\Program Files
ProgramFiles(x86)=C:\Program Files (x86)
ProgramW6432=C:\Program Files
PROMPT=$P$G
PSModulePath=C:\Windows\system32\WindowsPowerShell\v1.0\Modules\
PUBLIC=C:\Users\Public
SESSIONNAME=Console
SystemDrive=C:
SystemRoot=C:\Windows
TEMP=C:\Users\_JSMITH~1_\AppData\Local\Temp
TMP=C:\Users\_JSMITH~1_\AppData\Local\Temp
USERDNSDOMAIN=MYDOMAIN.COM
USERDOMAIN=MYDOMAIN
USERNAME=<UserName>
USERPROFILE=C:\Users\<UserName>
windir=C:\Windows
windows_tracing_flags=3
PowerShell
[PS] C:\>get-variable
Name Value
---- -----
$ ~\history.csv
? True
^ Get-History
_
args {}
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ConfigurationPath C:\Program Files\Microsoft\Exchange Server\V14\bin\Microsoft.Exchange.Configuration.O...
ConfirmPreference High
connectedFqdn MYSERVER.mydomain.com
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ConsoleFileName
DebugPreference SilentlyContinue
Error {The term 'testpath' is not recognized as the name of a cmdlet, function, script file...
ErrorActionPreference Continue
ErrorView NormalView
exbin C:\Program Files\Microsoft\Exchange Server\V14\bin\
ExecutionContext System.Management.Automation.EngineIntrinsics
exinstall C:\Program Files\Microsoft\Exchange Server\V14\
exrandom System.Random
exscripts C:\Program Files\Microsoft\Exchange Server\V14\scripts\
false False
FormatEnumerationLimit 16
getLiveIDCredCode using System;...
`HOME M:\`
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importResults lbexchange.medlinkmanagement.com
input System.Collections.ArrayList+ArrayListEnumeratorSimple
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MaximumDriveCount 4096
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MaximumFunctionCount 4096
MaximumHistoryCount 64
MaximumVariableCount 4096
MyInvocation System.Management.Automation.InvocationInfo
NestedPromptLevel 0
null
OutputEncoding System.Text.ASCIIEncoding
partialTypeFile C:\Program Files\Microsoft\Exchange Server\V14\bin\Exchange.partial.Types.ps1xml
PID 8600
PROFILE \\AppServer\Users\User Name\Data\Documents\WindowsPowerShell\Microsoft.PowerShell_pr...
ProgressPreference Continue
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PSEmailServer
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PSSessionConfigurationName http://schemas.microsoft.com/powershell/Microsoft.PowerShell
PSSessionOption System.Management.Automation.Remoting.PSSessionOption
PSUICulture en-US
PSVersionTable {CLRVersion, BuildVersion, PSVersion, WSManStackVersion, PSCompatibleVersions, Serial...
PWD C:\
RemoteExchange_LocalizedStr... {res_0003, res_help_for_cmdlet, res_0005, res_0007, res_0009, res_general_help, res_t...
remoteSession System.Management.Automation.Runspaces.PSSession
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ReportErrorShowSource 1
ReportErrorShowStackTrace 0
sessionOptionsTimeout 180000
ShellId Microsoft.PowerShell
StackTrace at System.Management.Automation.CommandDiscovery.LookupCommandInfo(String commandN...
true True
typeFilePath C:\Program Files\Microsoft\Exchange Server\V14\bin\exchange.types.ps1xml
typeListToCheck
typeLoadResult True
VerbosePreference SilentlyContinue
WarningPreference Continue
WhatIfPreference False