What is the difference between and in a cmd file

Question

I recently included a line similar to this in a  cmd file   for  f   f in   dir  b   directory   sql   DO sqlcmd -b -o    directory output   f txt  -i    directory   f    Originally I had only used  f  and it would work fine when run on the command line  but not when run through the file   When I switched to   f  it worked in the file   Just wondering what the difference is

User · Answer

In DOS you couldn t use environment variables on the command line  only in batch files  where they used the   sign as a delimiter  If you wanted a literal   sign in a batch file  e g  in an echo statement  you needed to double it   This carried over to Windows NT which allowed environment variables on the command line  however for backwards compatibility you still need to double your   signs in a  cmd file

User · Answer

Explanation in more details can be found in an archived Microsoft KB article    Three things to know    The percent sign is used in batch files to represent command line parameters   1   2      Two percent signs with any characters in between them are interpreted as a variable   echo  myvar  Two percent signs without anything in between  in a batch file  are treated like a single percent sign in a command  not a batch file     f     Why s that   For example  if we execute your  simplified  command line  FOR  f  f in   dir  b     DO somecommand  f   in a batch file  rule 2 would try to interpret   f in   dir  b     DO somecommand     as a variable  In order to prevent that  you have to apply rule 3 and escape the   with an second     FOR  f   f in   dir  b     DO somecommand   f

[batch-file] What is the difference between % and %% in a cmd file?

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