Move files into folders based on patterns

How to move files ending with a number into folders ending with numbers

Create 36 files which have three different starts and 12 different ends followed by an extension

touch {first,second,third}_{01..12}.tif

Copy files with the same number ending into folder with the same numbers

for file in *; do install -D "$file" "${file: -6:2}/${file}"; done

Explanation:

1. {01...10} generates sequence of numbers

2. ${string:offset:length} with a caveat, negative offset needs to be separated by space from the colon

3. install -D is like a copy (cp) command, but enables you to create the folder at the same time (and also the permissions and ownerships)

Copy the files with the same beginning (before underscore) into folders with the same beginning

regex='(.*)_(.*).tif';
for file in *;
do 
if [[ $file =~ $regex ]]
then install -D "$file" "${BASH_REMATCH[1]}/${file}";
fi
done

Explanation:

1. (.*) means any character folowed by anything

2. $file in the [[ ]]` syntax does not need to be quoted, works with a space also when it is a file

3. BASH_REMATCH [0] is the full string [1] is the first bit recognized [2] is the second bit recognized