Batch file to comment specific lines into a text file

Hi Experts,

Happy cristmas for all, and hope we find all the happiness, health and money (lotof money $$$)  :D

Please, i need to do a batch file like that :

MyBatchFile.bat    file.txt    FileWithLineToComment.txt

Where :

FileWithLineToComment.txt
     it's a text file, this one containall the lines text (not numbers of line) that we need to comment.

MyFile.txt:
   Containe all the lines

MyBatchFile.bat
   Is the program that i need to write. This batch file will :
  1- open FileWithLineToComment.txt, and read line by line
  2- for each line we read, we will search it into the "MyFile.txt"
  3- one time we find it we will add " // " in the first of the find line, and like that it will be
comment.
 


Exemple :

MyFile.txt Containe :

123
34
12
153
123
757

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FileWithLineToComment.txt

12
757

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if i do this command line :

MyBatchFile.bat    file.txt    FileWithLineToComment.txt

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MyFile.txt   will be like that:
 

123
34
//12
153
123
//757

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Hope you can help me

Thanks