You need to use
FOR to iterate over the elements you want to work with. See How to loop through files matching wildcard in batch file for details.
Once you have that part solved, you'll want to create the filename of your
.txt file. The command line documentation of
FOR can help us here:
In addition, substitution of FOR variable references has been enhanced.
You can now use the following optional syntax:
%~I - expands %I removing any surrounding quotes (")
%~fI - expands %I to a fully qualified path name
%~dI - expands %I to a drive letter only
%~pI - expands %I to a path only
%~nI - expands %I to a file name only
The last entry is what we want. We want to cut off the
.avi, so we use
~n in our variable to get only the name. This is where the
%%~nf.txt comes from.
We start with
%%f, the current filename. Then we cut off the extension with
%%~nf and tack on the
The last problem is when you try to solve it all on one line, like:
FOR %%f IN (*.avi) DO ECHO HAPPY > %%~nf.txt
That wouldn't work, because the shell will interpret the
> and start outputting to that file instantly, which is not what we want. We want the
ECHO to be processed for every single file, so I simply split it into multiple lines.
REM Iterate over all *.avi file in the current directory
FOR %%f IN (*.avi) DO (
REM Cut off the extension from %%f, tack on .txt and
REM use it as the filename for our HAPPY output
ECHO HAPPY > %%~nf.txt