diff --git a/swh/graph/cli.py b/swh/graph/cli.py
index f84c6cc..4f654df 100644
--- a/swh/graph/cli.py
+++ b/swh/graph/cli.py
@@ -1,114 +1,115 @@
 # Copyright (C) 2019  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 sys
 
 from swh.core.cli import CONTEXT_SETTINGS, AliasedGroup
 from swh.graph import client
-from swh.graph.pid import PidToIntMap, IntToPidMap
+from swh.graph.pid import PidToIntMap, IntToPidMap, PID_BIN_SIZE
 
 
 @click.group(name='graph', context_settings=CONTEXT_SETTINGS,
              cls=AliasedGroup)
 @click.pass_context
 def cli(ctx):
     """Software Heritage graph tools."""
     ctx.ensure_object(dict)
 
 
 @cli.command('api-client')
 @click.option('--host', default='localhost', help='Graph server host')
 @click.option('--port', default='5009', help='Graph server port')
 @click.pass_context
 def api_client(ctx, host, port):
     """Client for the Software Heritage Graph REST service
 
     """
     url = 'http://{}:{}'.format(host, port)
     app = client.RemoteGraphClient(url)
 
     # TODO: run web app
     print(app.stats())
 
 
 @cli.group('map')
 @click.pass_context
 def map(ctx):
     """Manage swh-graph on-disk maps"""
     pass
 
 
 def dump_pid2int(filename):
     for (pid, int) in PidToIntMap(filename):
         print('{}\t{}'.format(pid, int))
 
 
 def dump_int2pid(filename):
     for (int, pid) in enumerate(IntToPidMap(filename)):
         print('{}\t{}'.format(int, pid))
 
 
 def restore_pid2int(filename):
     """read a textual PID->int map from stdin and write its binary version to
     filename
 
     """
     with open(filename, 'wb') as dst:
         for line in sys.stdin:
             (str_pid, str_int) = line.split()
             PidToIntMap.write_record(dst, str_pid, int(str_int))
 
 
 def restore_int2pid(filename):
     """read a textual int->PID map from stdin and write its binary version to
     filename
 
     """
     with open(filename, 'wb') as dst:
         for line in sys.stdin:
-            (_str_int, str_pid) = line.split()
+            (str_int, str_pid) = line.split()
+            dst.seek(int(str_int) * PID_BIN_SIZE)
             IntToPidMap.write_record(dst, str_pid)
 
 
 @map.command('dump')
 @click.option('--type', '-t', 'map_type', required=True,
               type=click.Choice(['pid2int', 'int2pid']),
               help='type of map to dump')
 @click.argument('filename', required=True, type=click.Path(exists=True))
 @click.pass_context
 def dump_map(ctx, map_type, filename):
     """dump a binary PID<->int map to textual format"""
     if map_type == 'pid2int':
         dump_pid2int(filename)
     elif map_type == 'int2pid':
         dump_int2pid(filename)
     else:
         raise ValueError('invalid map type: ' + map_type)
     pass
 
 
 @map.command('restore')
 @click.option('--type', '-t', 'map_type', required=True,
               type=click.Choice(['pid2int', 'int2pid']),
               help='type of map to dump')
 @click.argument('filename', required=True, type=click.Path())
 @click.pass_context
 def restore_map(ctx, map_type, filename):
     """restore a binary PID<->int map from textual format"""
     if map_type == 'pid2int':
         restore_pid2int(filename)
     elif map_type == 'int2pid':
         restore_int2pid(filename)
     else:
         raise ValueError('invalid map type: ' + map_type)
 
 
 def main():
     return cli(auto_envvar_prefix='SWH_GRAPH')
 
 
 if __name__ == '__main__':
     main()