How to remove trailing and leading whitespace for

Question

I know how to do this when the variable is pre-defined. However, when asking for the user to enter in some kind of input, how do I trim leading and trailing whitespace? This is what I have so far:

@echo off

set /p input=:
echo. The input is %input% before

::trim left whitespace
for /f "tokens=* delims= " %%a in ("%input%") do set input=%%a
::trim right whitespace (up to 100 spaces at the end)
for /l %%a in (1,1,100) do if "!input:~-1!"==" " set input=!input:~0,-1! 

echo. The input is %input% after

pause

Answer 1

set newVarNoSpaces=%someVarWithSpaces: =%

Answer 2

The :trimAll subroutine below:

• trims leading and trailing tabs and spaces from the string passed to it
• can be safely CALLed with delayed expansion disabled or enabled
• handles poison characters (eg, !, %, ^, etc.)
• CRs and LFs are not supported

Read comments for references and info.

@echo off & setLocal enableExtensions disableDelayedExpansion
:: https://www.dostips.com/forum/viewtopic.php?t=4308
(call;) %= sets errorLevel to 0 =%
(set lf=^
%= BLANK LINE REQUIRED =%
)
:: kudos to Carlos for superior method of capturing CR
:: https://www.dostips.com/forum/viewtopic.php?p=40757#p40757
set "cr=" & if not defined cr for /f "skip=1" %%C in (
    'echo(^|replace ? . /w /u'
) do set "cr=%%C"

set ^"orig=  !random!  !  ^^!  ^^^^!  ^"^^  ^&^"^&  ^^^" %%os%%  ^"

call :trimAll res1 orig
setLocal enableDelayedExpansion
call :trimAll res2 orig
echo(orig: [!orig!]
echo(res1: [!res1!]
echo(res2: [!res2!]
endLocal

endLocal & goto :EOF

:trimAll result= original=
:: trims leading and trailing whitespace from a string
:: special thanks to Jeb for
:: https://stackoverflow.com/a/8257951
setLocal
set "ddx=!" %= is delayed expansion enabled or disabled? =%
setLocal enableDelayedExpansion
set "die=" & if not defined %2 (
    >&2 echo(  ERROR: var "%2" not defined & set "die=1"
) else set "str=!%2!" %= if =%

if not defined die for %%L in ("!lf!") ^
do if "!str!" neq "!str:%%~L=!" (
    >&2 echo(  ERROR: var "%2" contains linefeeds & set "die=1"
) %= if =%

if not defined die for %%C in ("!cr!") ^
do if "!str!" neq "!str:%%~C=!" (
    >&2 echo(  ERROR: var "%2" contains carriage returns
    set "die=1"
) %= if =%

if defined die goto die

(for /f eol^= %%A in ("!str!") do rem nop
) || (
    >&2 echo(WARNING: var "%2" consists entirely of whitespace
    endLocal & endLocal & set "%1=" & exit /b 0
) %= cond exec =%

:: prepare string for trimming...
:: double carets
set "str=!str:^=^^^^!"
:: double quotes
set "str=!str:"=""!"
:: escape exclaims
set "str=%str:!=^^^!%" !

:: act of CALLing subfunction with
:: expanded string trims trailing whitespace
call :_trimAll "%%str%%

:: prepare string to be passed over endLocal boundary...
:: double carets again if delayed expansion enabled
if not defined ddx set "str=!str:^=^^^^!"
:: escape exclaims again if delayed expansion enabled
if not defined ddx set "str=%str:!=^^^!%" !
:: restore quotes
set "str=!str:""="!"

:: pass string over endLocal boundary and trim leading whitespace
for /f tokens^=*^ eol^= %%a in ("!str!") do (
    endLocal & endLocal & set "%1=%%a" !
) %= for /f =%
exit /b 0

:die
endLocal & endLocal & set "%1=" & exit /b 1

:_trimAll
:: subfunction
:: trailing exclaim is required as explained by Jeb at
:: https://www.dostips.com/forum/viewtopic.php?p=6933#p6933
set "str=%~1" !
exit /b 0

HTH and HNY! ;)

Answer 3

You need to enable delayed expansion. Try this:

@echo off
setlocal enabledelayedexpansion
:blah
set /p input=:
echo."%input%"
for /f "tokens=* delims= " %%a in ("%input%") do set input=%%a
for /l %%a in (1,1,100) do if "!input:~-1!"==" " set input=!input:~0,-1!
echo."%input%"
pause
goto blah

Answer 4

You can also strip whitespace by passing in those variables with whitespace as parameters into a sub and then inside your sub simply set them again with the passed in parameters.

@echo off 
set "a=    apple      "
set "b=     banana    "
echo [%a%]
echo [%b%]
call :Strip %a% %b%
pause
goto :EOF

:Strip
set a=%1
set b=%2
echo [%a%]
echo [%b%]

----------------
Results....
[    apple      ]
[     banana    ]
[apple]
[banana]
Press any key to continue . . .

Answer 5

The solution below works very well for me.

Only 4 lines and works with most (all?) characters.

---

Solution:

:Trim
SetLocal EnableDelayedExpansion
set Params=%*
for /f "tokens=1*" %%a in ("!Params!") do EndLocal & set %1=%%b
exit /b

---

Test:

@echo off

call :Test1 & call :Test2 & call :Test3 & exit /b

:Trim
SetLocal EnableDelayedExpansion
set Params=%*
for /f "tokens=1*" %%a in ("!Params!") do EndLocal & set %1=%%b
exit /b

:Test1
set Value=   a b c   
set Expected=a b c
call :Trim Actual %Value%
if "%Expected%" == "%Actual%" (echo Test1 passed) else (echo Test1 failed)
exit /b

:Test2
SetLocal EnableDelayedExpansion
set Value=   a \ / : * ? " ' < > | ` ~ @ # $ [ ] & ( ) + - _ = z    
set Expected=a \ / : * ? " ' < > | ` ~ @ # $ [ ] & ( ) + - _ = z
call :Trim Actual !Value!
if !Expected! == !Actual! (echo Test2 passed) else (echo Test2 failed)
exit /b

:Test3
set /p Value="Enter string to trim: " %=%
echo Before: [%Value%]
call :Trim Value %Value%
echo After : [%Value%]

Answer 6

  @echo off & setlocal enableextensions
  rem enabledelayedexpansion
  set S=  This  is  a  test
  echo %S%.
  for /f "tokens=* delims= " %%a in ('echo %S%') do set S=%%a
  echo %S%.
  endlocal & goto :EOF

from http://www.netikka.net/tsneti/info/tscmd079.htm

for removing leading spaces.