This is a simple Makefile spec that allows you to transform every .tsv file in your current directory to a .csv with a given tsv2csv python script

Makefile

# You can call this with:
# make -j N all_csv
# where N can be the number of processors you wish to use in parallel


# This Make rule uses the Python script `tsv2csv.py` to turn the first argument (the .tsv file) and dumps it to the output file
%.csv: %.tsv
        python tsv2csv.py $< > $@

# This gets all files in this directory that end in .tsv
TSV_SOURCES:=$(shell find $(SOURCEDIR) -name '*.tsv')

# This makes all of those .tsv files .csv and stores them in a variable
CSV_SOURCES:=$(TSV_SOURCES:.tsv=.csv)

# This is a dummy target that runs the command on each file
all_csv: $(CSV_SOURCES)

tsv2csv.py

# Essentially copied from here: https://gist.github.com/nsonnad/7598574

import sys
import csv

csv.field_size_limit(sys.maxsize)

# tabin = csv.reader(sys.stdin, dialect=csv.excel_tab)

file_in = sys.argv[1]

# Handle newlines properly
tabin = csv.reader(open(file_in, 'rU'), dialect=csv.excel_tab)
commaout = csv.writer(sys.stdout, dialect=csv.excel)

for row in tabin:
  commaout.writerow(row)