How to loop through files matching wildcard in batch file

Question

Assuming you have two programs that process the two files, process_in.exe and process_out.exe:

for %%f in (*.in) do (
    echo %%~nf
    process_in "%%~nf.in"
    process_out "%%~nf.out"
)

%%~nf is a substitution modifier, that expands %f to a file name only. See other modifiers in https://technet.microsoft.com/en-us/library/bb490909.aspx (midway down the page) or just in the next answer.

You can use this line to print the contents of your desktop:

FOR %%I in (C:\windows\desktop\*.*) DO echo %%I 

Once you have the %%I variable it's easy to perform a command on it (just replace the word echo with your program)

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 (directory with \)
%~nI        - expands %I to a file name only
%~xI        - expands %I to a file extension only
%~sI        - expanded path contains short names only
%~aI        - expands %I to file attributes of file
%~tI        - expands %I to date/time of file
%~zI        - expands %I to size of file
%~$PATH:I   - searches the directories listed in the PATH
               environment variable and expands %I to the
               fully qualified name of the first one found.
               If the environment variable name is not
               defined or the file is not found by the
               search, then this modifier expands to the
               empty string

https://ss64.com/nt/syntax-args.html

In the above examples %I and PATH can be replaced by other valid values. The %~ syntax is terminated by a valid FOR variable name. Picking upper case variable names like %I makes it more readable and avoids confusion with the modifiers, which are not case sensitive.

You can get the full documentation by typing FOR /?

Easiest way, as I see it, is to use a for loop that calls a second batch file for processing, passing that second file the base name.

According to the for /? help, basename can be extracted using the nifty ~n option. So, the base script would read:

for %%f in (*.in) do call process.cmd %%~nf

Then, in process.cmd, assume that %0 contains the base name and act accordingly. For example:

echo The file is %0
copy %0.in %0.out
ren %0.out monkeys_are_cool.txt

There might be a better way to do this in one script, but I've always been a bit hazy on how to pull of multiple commands in a single for loop in a batch file.

EDIT: That's fantastic! I had somehow missed the page in the docs that showed that you could do multi-line blocks in a FOR loop. I am going to go have to go back and rewrite some batch files now...

Expanding on Nathans post. The following will do the job lot in one batch file.

@echo off

if %1.==Sub. goto %2

for %%f in (*.in) do call %0 Sub action %%~nf
goto end

:action
echo The file is %3
copy %3.in %3.out
ren %3.out monkeys_are_cool.txt

:end

There is a tool usually used in MS Servers (as far as I can remember) called forfiles:

The link above contains help as well as a link to the microsoft download page.

The code below filters filenames starting with given substring. It could be changed to fit different needs by working on subfname substring extraction and IF statement:

echo off
rem filter all files not starting with the prefix 'dat'
setlocal enabledelayedexpansion
FOR /R your-folder-fullpath %%F IN (*.*) DO (
set fname=%%~nF
set subfname=!fname:~0,3!
IF NOT "!subfname!" == "dat" echo "%%F"
)
pause