Shell Script — Get all files modified after

as simple as:

find . -mtime -1 | xargs tar --no-recursion -czf myfile.tgz

where find . -mtime -1 will select all the files in (recursively) current directory modified day before. you can use fractions, for example:

find . -mtime -1.5 | xargs tar --no-recursion -czf myfile.tgz