select lines of data out of seperate csv files

Hi, I have +-300 csv data files, containing +- 1 million lines each. Currently, when I do data analysis, my first step is: I select the data from all csv files seperately by loading a csv file in excel, set up filters, copy the lines which are filtered to a sheet and continue with the next csv file etc. This selection of data takes me hours. If it is possible, I would like to get a tool, in which I can: - set up filter rules: for example,column x = y, column x contains y, column x + c > column y etc - select a directory (with csv files) and it automatically processes all files - gives me a csv file containing the filtered lines from all csv files.