Batch file: Find if substring is in string (not in a file)

Question

Yes, you can use substitutions and check against the original string:

if not x%str1:bcd=%==x%str1% echo It contains bcd

The %str1:bcd=% bit will replace a bcd in str1 with an empty string, making it different from the original.

If the original didn't contain a bcd string in it, the modified version will be identical.

Testing with the following script will show it in action:

@setlocal enableextensions enabledelayedexpansion
@echo off
set str1=%1
if not x%str1:bcd=%==x%str1% echo It contains bcd
endlocal

And the results of various runs:

c:\testarea> testprog hello

c:\testarea> testprog abcdef
It contains bcd

c:\testarea> testprog bcd
It contains bcd

A couple of notes:

• The if statement is the meat of this solution, everything else is support stuff.
• The x before the two sides of the equality is to ensure that the string bcd works okay. It also protects against certain "improper" starting characters.

You can pipe the source string to findstr and check the value of ERRORLEVEL to see if the pattern string was found. A value of zero indicates success and the pattern was found. Here is an example:

::
: Y.CMD - Test if pattern in string
: P1 - the pattern
: P2 - the string to check
::
@echo off

echo.%2 | findstr /C:"%1" 1>nul

if errorlevel 1 (
  echo. got one - pattern not found
) ELSE (
  echo. got zero - found pattern
)

When this is run in CMD.EXE, we get:

C:\DemoDev>y pqrs "abc def pqr 123"
 got one - pattern not found

C:\DemoDev>y pqr "abc def pqr 123" 
 got zero - found pattern

I usually do something like this:

Echo.%1 | findstr /C:"%2">nul && (
    REM TRUE
) || (
    REM FALSE
)

Example:

Echo.Hello world | findstr /C:"world">nul && (
    Echo.TRUE
) || (
    Echo.FALSE
)

Echo.Hello world | findstr /C:"World">nul && (Echo.TRUE) || (Echo.FALSE)

Output:

TRUE
FALSE

I don't know if this is the best way.

For compatibility and ease of use it's often better to use FIND to do this.

You must also consider if you would like to match case sensitively or case insensitively.

The method with 78 points (I believe I was referring to paxdiablo's post) will only match Case Sensitively, so you must put a separate check for every case variation for every possible iteration you may want to match.

( What a pain! At only 3 letters that means 9 different tests in order to accomplish the check! )

In addition, many times it is preferable to match command output, a variable in a loop, or the value of a pointer variable in your batch/CMD which is not as straight forward.

For these reasons this is a preferable alternative methodology:

Use: Find [/I] [/V] "Characters to Match"

[/I] (case Insensitive) [/V] (Must NOT contain the characters)

As Single Line:

ECHO.%Variable% | FIND /I "ABC">Nul && ( Echo.Found "ABC" ) || ( Echo.Did not find "ABC" )

Multi-line:

ECHO.%Variable%| FIND /I "ABC">Nul && ( 
  Echo.Found "ABC"
) || (
  Echo.Did not find "ABC"
)

As mentioned this is great for things which are not in variables which allow string substitution as well:

FOR %A IN (
  "Some long string with Spaces does not contain the expected string"
  oihu AljB
  lojkAbCk
  Something_Else
 "Going to evaluate this entire string for ABC as well!"
) DO (
  ECHO.%~A| FIND /I "ABC">Nul && (
    Echo.Found "ABC" in "%A"
  ) || ( Echo.Did not find "ABC" )
)

Output From a command:

    NLTest | FIND /I "ABC">Nul && ( Echo.Found "ABC" ) || ( Echo.Did not find "ABC" )

As you can see this is the superior way to handle the check for multiple reasons.