Bash: reading files and moving into sub-directory - macos

Question

I have around 1000 files (png) and need to move them into the corresponding directory and their sub-directory.
I do have 26 directories (A - Z) and below each directory the complete alphabet A-Z again. File names are 6 characters/digits long and have a png extension, e.g. e.g. AH2BC0.png
I would need to move the file AH2BC0.png into the directory A and within that directory into the sub-directory H, e.g.A->H->AH2BC0.png.
I have created following script which is not really working as expected:
#!/bin/bash
ls >LISTE.txt
for i in LISTE.txt; do
a=$(cat $i | cut -b 1 | tr '[:lower:]' '[:upper:]')
b=$(cat $i | cut -b 2 | tr '[:lower:]' '[:upper:]')
mkdir -p $a/$b
cat $i | xargs mv $a/$b
rm $i
done
Problem is that a) the sub-directory is not created and b) the files are not moved. Any suggestions or better ideas for the script?
Thanks
PS: I guess it's obvious that it's quite some years ago that I have created any bash scripts or coded so please bear with me.
PSS: working on MAC OSX bash 3.2

Answer 1

There's already a post showing a better program to do what you want but I thought I'd show you how to fix yours. Hopefully you'll find it informative.
#!/bin/bash
ls >LISTE.txt
for i in LISTE.txt; do
This loops over the single value LISTE.txt; replace it with:
for i in $(cat LISTE.txt); do
to loop over the contents of the file instead.
a=$(cat $i | cut -b 1 | tr '[:lower:]' '[:upper:]')
b=$(cat $i | cut -b 2 | tr '[:lower:]' '[:upper:]')
You want to use echo rather than cat in the above two lines, as you're after the name of the file not its content.
mkdir -p $a/$b
cat $i | xargs mv $a/$b
I don't think the above line does what you think it does... It will attempt to rename the $a/$b directory to C, where C is the content of file $i. Replace it with:
mv $i $a/$b
The following line is not needed:
rm $i
So simply delete it. It would only be necessary if you copied rather than moved the files using mv.
done
Here's your complete program after the changes I've suggested.
#!/bin/bash
ls >LISTE.txt
for i in $(cat LISTE.txt); do
a=$(echo $i | cut -b 1 | tr '[:lower:]' '[:upper:]')
b=$(echo $i | cut -b 2 | tr '[:lower:]' '[:upper:]')
mkdir -p $a/$b
mv $i $a/$b
done

Answer 2

#!/bin/bash
for item in *; do
first=${item:0:1}
second=${item:1:1}
folder="$first/$second"
mkdir -p $folder
mv $item $folder/
done