Use the syntax below to edit and replace the characters assigned to a string variable, also known as String Substitution.
Syntax
%variable:StrToFind=NewStr%
%~[param_ext]$variable:Param
Key
StrToFind : The characters we are looking for (not case sensitive).
NewStr : The chars to replace with (if any).
variable : The environment variable.
param_ext : Any filename Parameter Extension.
Param : A command line parameter (e.g. 1).
This Edit/Replace syntax can be used anywhere that you would use the %variable% such as ECHOing the variable to screen or setting one variable = another.
param_ext cannot be %* which typically represents a whole set of parameters, but this is easily worked around by setting a variable=%*
"StrToFind" can begin with an asterisk, in which case it will replace
all characters to the left of "StrToFind".
NewStr can be left blank to delete characters, alternatively include ECHO: in NewStr if you need to generate a CR/newline in the output:
In all cases the string matching is NOT case sensitive, so the string ABC will match abc.
Using both an asterisk and setting NewStr=null will enable you to construct a left$() or right$() function using this syntax.
Examples:
The variable _test containing 12345abcabc is
used for all the following examples:
::Replace '12345' with 'Hello ' SET "_test=12345abcABC" SET "_result=%_test:12345=Hello %" ECHO %_result% =Hello abcABC ::Replace the character string 'ab' with 'xy' SET "_test=12345abcABC" SET "_result=%_test:ab=xy%" ECHO %_result% =12345xycxyC ::Delete the character string 'ab' SET "_test=12345abcABC" SET "_result=%_test:ab=%" ECHO %_result% =12345cC ::Delete the character string 'ab' and everything before it SET "_test=12345abcabc" SET "_result=%_test:*ab=%" ECHO %_result% =cabc ::Replace the character string 'ab' and everything before it with 'XY' SET "_test=12345abcabc" SET "_result=%_test:*ab=XY%" ECHO %_result% =XYcabc :: To remove characters from the right hand side of a string is :: a two step process and requires the use of a CALL statement :: e.g. SET _test=The quick brown fox jumps over the lazy dog :: To delete everything after the string 'brown' :: first delete 'brown' and everything before it SET "_endbit=%_test:*brown=%" Echo We dont want: [%_endbit%] ::Now remove this from the original string CALL SET "_result=%%_test:%_endbit%=%%" echo %_result%
The examples above assume the default Expansion of variables, if you are using DelayedExpansion then you can modify variables within a single loop/expression. Use the syntax: !_variable! instead of %_variable%
Rename a set of files (fred001.txt – fred999.txt) with a different prefix, this is similar to but more flexible than a wildcard rename,
via Raymond Chen
Setlocal EnableDelayedExpansion
for %%i in (fred*.txt) do set "_=%%i" & ren "%%i" "!_:fred=wilma!"One other advantage of DelayedExpansion is that it will allow you to replace the % character, it will still have to be escaped as %% but the replace action will then treat it like any other character:
Replace the letter P with a percent symbol:
Setlocal EnableDelayedExpansion
_demo=somePdemoPtextP
_demo=!_demo:P=%%!
To delete space characters use the same syntax as above:
SET "_no_spaces=%_some_var: =%"
To test for the existence of a value we can use a temporary variable, delete the string we are looking for (if it exists) and then compare the two variables with EQU
Example: test for the existence of the string "London" in a variable containing text (that could be in any order) "Aberdeen, London, Edinburgh"
Set "_cities=Aberdeen, London, Edinburgh"
:: Remove London if found
Set "_dummy=%_cities:London=%"
IF NOT %_dummy% == %_cities% (ECHO London was found.) ELSE (ECHO London was not found.)
The %PATH% variable contains a list of folder names.
If you have a parameter containing a valid 'folder' this can be compared with the PATH variable.
This is done using the syntax: $variable:parameter
Example%PATH% = C:\Windows\system32;C:\Windows;C:\utils\jdk\bin
batch parameter %1 = C:\utils\jdk\bin
To get the drive and Path
ECHO %~dp$PATH:1
This will either return "C:\utils\jdk\bin" or a NULL if the item is not found in the %PATH%
If the batch parameter was supplied as %2 then this would be: ECHO %~dp$PATH:2
This syntax can be applied where:
- The parameter is any valid parameter (%1 %2 %G) but it must contain a Full Path (not a pathname)
- The variable is %PATH% or any other variable that contains one or more Paths or pathnames separated by semicolons ;
- If nothing is found by the search, then this will return an empty string (NULL)
Be wary of using the syntax on this page to modify the PATH - the User path can be edited, but the System path remains read-only for most users.
You can use the %variable: syntax and provide each of the parameters from other variables, for example if you have
SET "_FullString=The ballad of John and Yoko"
SET "_Search=John"
To remove the %_search% string from the%_FullString% you might try:SET "_result=%_FullString:~%_Search%=%"Unfortunately this will not work because the : syntax expects a value not a variable.
To work around this use the CALL command, in this case the CALL replaces the variable shown in bold with its value:SET "_FullString=The ballad of John and Yoko" SET "_Search=John" CALL SET "_result=%%_FullString:%_Search%=%%"
:: If nothing was removed then the search string was not found. If /i "%_result%"=="%_FullString%" (Echo String not found) ELSE (Echo String found)
“A phony smile will never replace honest integrity” ~ Bob Martinelli
PATH - Display or set a search path for executable files.
How-to: SUBSTRING of a variable :~
How-to: PARAMETERS - Filename Parameter Extensions.
How-to: strlen.cmd - Get string length.
How-to: ToLower.cmd - Lower case a String.