Batch file for loop string replacement - windows

Question

I have a batch file that take a directory path as a parameter.
In that file folder, there are any number of .ai.pdf or .pdf files that I need to convert to jpg's. The conversion is not my issue (I am using imageMagick) , but lopping off the full extension is.
I need to be able to either take off the full .ai.pdf (7 characters) or .pdf (4 characters) from the file name and replace it with .jpg I cannot use just ~n in the for loop because it will not take off the .ai in an instance with there is an .ai.pdf (results in file name.ai where I need just the file name)
There are quite a few posts on StackOverFlow about this
StackOverFlow Example
but no matter what I attempt to try, I get an error when truncating the appropriate amount of extension off of the file name.
Here is my code. This is the first major batch file I have ever created, so I am open to anything, other than installing more programs to do the work.
The thing that kills me, is I had this working and in the shuffle from one server to another and a week of vacation, the working code got....misplaced.
#echo off
SETLOCAL ENABLEDELAYEDEXPANSION
set dir1=%1
echo recieved !dir1!
for /R %dir1% %%a in (*.pdf) DO (
echo file found !a!
set b=th_%%~nxa
if x%b:ai.pdf=%==x%b% set b=%%~dpa!b:~0,-7!
if not x%b:ai.pdf=%==x%b% set b=%%~dpa!b:~0,-4!
REM convert -density 64 "%%a" +matte -resize 15%% "!b!.jpg"
#echo !b! converted
)
ENDLOCAL
the file tells me that %~dpa!b:~0,-7! is an invalid substitution
Any ideas? Thanks for the help!

Answer 1

A few things first:
!a! and %%a are two different variables.
if x%b:ai.pdf=%==x%b% does not mean what you think it does. That will only be true when %b% does NOT contain .ai.pdf.
Again, if not x%b:ai.pdf=%==x%b% does not mean what you think. This is true when %b% DOES contain .ai.pdf.
There is no need to do any verification and cutting, just search and replace. ( That is what the %y:x=z% notation does, in this example it replaces every x within %y% with a z.) Let search and replace do the verification. It will only replace what matches the search. That will speed up the your batch file.
Lastly, since you are inside a () code block you will need to use the delayed Expansion turned on with your setlocal statement. This is because everything inside a code block is treated as if it were on a single line. That means that if you change a variable inside a code block, you will not be able to see the new value using the % notation. Instead you need to replace the %'s with !'s. For instance...
setlocal enableDelayedExpansion
set x=Hello
(
set x=Goodbye
echo I don't know why you say "!x!", I say "%x%".
)
...will give you the old Beatles lyric...
I don't know why you say "Goodbye", I say "Hello".
Anyway, on to your answer:
#echo off
SETLOCAL ENABLEDELAYEDEXPANSION
set dir1=%1
echo recieved !dir1!
for /R %dir1% %%a in (*.pdf) DO (
:: Adding a colon to the end of the filename allows the extension to be ID'd
: without explicitly looking at it with an IF statement, while simultaneously
:: avoiding similar looking character groupings inside the filename.
set b=th_%%~nxa:
:: No need to check for case, the substitution will do that for you.
set b=!b:.ai.pdf:=.jpg!
set b=!b:.pdf:=.jpg!
REM convert -density 64 "%%a" +matte -resize 15%% "!b!"
echo %%a converted into !b!
)
ENDLOCAL
The drawback is that both the files...
X.ai.pdf
X.pdf
...will be translated into th_X.jpg, creating the possibility of duplicate filenames for two different files.
But that's intrinsic to your concept of treating both types of filenames the same. If you don't have a method for avoiding this sort of duplication it might not be a bad idea to leave the .ai on the file, thereby creating two files: th_X.jpg and th_X.ai.jpg, eliminating the possibility of duplicate filenames.

Answer 2

Hm... would this work for you:
for /R %F in (*.pdf) do #for %G in ("%~nF") do #echo %~nxF ==^> %~nG.jpg
(as executed directly from cmd, if run from batch, replace % with %%).
This has a peculiar effect of changing the case of a file to case of a directory if there exists one with the same name as base name of your file (file.pdf will become FILE.jpg if you happen to have a subdirectory called FILE), but that's it (I think).
This also assumes your base names differ (so no file.ai.pdf and file.pdf in same directory)