Mag Gam <magaw...@gmail.com> writes: > I have 3 files which are constantly being updated therefore I use tail > -f /var/log/file1, tail -f /var/log/file2, and tail -f /var/log/file3 > > For 1 file I am able to manage by > tail -f /var/log/file1 | python prog.py > > prog.py looks like this: > f=sys.stdin > for line in f: > print line > > But how can I get data from /var/log/file2 and /var/log/file3 ?
Use shell tricks, e.g., with bash: yourpythonprog <(tail -f .../file1) <(tail -f .../file2) <(...) and let your prog open its three parameters like regular files (they are fifos actually). If your shell doesn't support <(...), create the fifos and redirect tail output before launching your prog. If you want "purer" python, launch the three "tail -f" with subprocess, and use the select module to get input (you didn't explain the logic you will follow to track three files---you may not need select if you expect one line from each file before waiting for the next line of any). > I prefer a native python way instead of doing tail -f Emulating tail will require a lot of stat/seeks, and finding lines will require an additional level of complexity. Also, tail -f has a cost [*]. The only way to avoid it is to use inotify, which seems to have a python interface, available at http://pyinotify.sourceforge.net/ (I've never used it). Again, emulating tail -f with inotify is significant work. -- Alain. [*] Paul Rubin is one of the authors, I think he reads this group. -- http://mail.python.org/mailman/listinfo/python-list
