diff --git a/ardumont/schedule_csv_range.py b/ardumont/schedule_csv_range.py
index 0823cb1..99136b8 100644
--- a/ardumont/schedule_csv_range.py
+++ b/ardumont/schedule_csv_range.py
@@ -1,46 +1,76 @@
 #!/usr/bin/env python3
 
 # Copyright (C) 2018  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 
 import click
+import random
 from math import floor
 
 
-@click.command()
-@click.option('--task-type', '-t', default='indexer_range_mimetype',
-              help='Add task type')
-@click.option('--policy', '-p', default='oneshot',
-              help='Task policy, either oneshot or recurring')
-@click.option('--number', '-n', default=10,
-              help='Number of ranges to compute')
-def main(task_type, policy, number):
-    """Compute ranges of sha1 (160 bits/20 bytes length)
+def sha1_ranges(number_ranges):
+    """Compute `number_ranges` random 'balanced' sha1 ranges.
+
+    Args:
+        number_ranges (int): Number of ranges to compute
+
+    Returns:
+        List[tuple] of hex [start, end] ranges.
 
     """
-    # bits_number = 10
     bits_number = 160
     bound_max = 2**bits_number - 1
-    step = floor(bound_max / number)
+    step = floor(bound_max / number_ranges)
     bound_max_minus = bound_max - step
 
     def to_hex(number):
         return '{:040x}'.format(number)
 
+    ranges = []
     for start, end in zip(
             range(0, bound_max_minus, step), range(step, bound_max, step)):
         hex_start = to_hex(start)
         hex_end = to_hex(end)
-        print('%s;%s;["%s", "%s"]' % (task_type, policy, hex_start, hex_end))
+        ranges.append((hex_start, hex_end))
 
     if end < bound_max:
         hex_start = to_hex(end)
         hex_end = to_hex(bound_max)
-        print('%s;%s;["%s", "%s"]' % (task_type, policy, hex_start, hex_end))
+        ranges.append((hex_start, hex_end))
+
+    random.shuffle(ranges)
+    return ranges
+
+
+@click.command()
+@click.option('--task-type', '-t', default='indexer_range_mimetype',
+              help='Add task type')
+@click.option('--policy', '-p', default='oneshot',
+              help='Task policy, either oneshot or recurring')
+@click.option('--number-ranges', '-n', default=10,
+              help='Number of ranges to compute')
+def main(task_type, policy, number_ranges):
+    """Compute `number-range` ranges of sha1 (160 bits/20 bytes length)
+       for a given `task-type` with a given `policy`.
+
+    Use sample:
+    $ python3 -m schedule_csv_range \
+              --task-type indexer_range_mimetype \
+              --policy recurring \
+              --number-ranges 100000 | head -2
+    indexer_range_mimetype;recurring;["1acba732df505dad980000000000000000000000", "1acc4ef88b9778f5200000000000000000000000"]  # noqa
+    indexer_range_mimetype;recurring;["2e4649906cca2ec6e00000000000000000000000", "2e46f15619114a0e680000000000000000000000"]  # noqa
+
+    Then actually schedule the tasks:
+    $ head -1 mimetype.prod.csv | python3 -m swh.scheduler.cli task schedule -c type -c policy -c args --delimiter ';' -
+
+    """
+    for r in sha1_ranges(number_ranges):
+        print('%s;%s;["%s", "%s"]' % (task_type, policy, r[0], r[1]))
 
 
 if __name__ == '__main__':
     main()