[Tutor] Reset while loop

[David]

Hi, not even sure if I can ask this very smartly but we shall try:
I was playing around with trying to create a python program like tail -f 
as discussed on the list. i came up with this;

def tail_it(bufsize=8192, linesep=__import__('os').linesep):
     f = None
     if f == None:
         f = open(tail_fname, 'rb')
         f.seek(0, 2)
         pos, tailsize = divmod(f.tell(), bufsize)
         if tailsize == 0:
             pos = max(0, pos-1)
         pos *= bufsize
         f.seek(pos)
         lines = f.read().split(linesep)
         x = len(lines)
         x = x-2
         print lines[x:]
         f.close()
     while True:
         new_time = os.stat(tail_fname).st_mtime
         if new_time > old_time:
             f = open(tail_fname, 'rb')
             f.seek(0, 2)
             pos, tailsize = divmod(f.tell(), bufsize)
             if tailsize == 0:
                 pos = max(0, pos-1)
             pos *= bufsize
             f.seek(pos)
             lines = f.read().split(linesep)
             x = len(lines)
             x = x-2
             print lines[x:]
             time.sleep(sec_to_wait)
             f.close()

[output]
['May  5 22:32:26 opteron su[5589]: pam_unix(su:session): session closed 
for user root', '']
['May  5 22:32:26 opteron su[5589]: pam_unix(su:session): session closed 
for user root', '']
['May  5 22:32:26 opteron su[5589]: pam_unix(su:session): session closed 
for user root', '']
['May  5 22:40:01 opteron cron[22996]: (root) CMD (test -x 
/usr/sbin/run-crons && /usr/sbin/run-crons )', '']
['May  5 22:40:01 opteron cron[22996]: (root) CMD (test -x 
/usr/sbin/run-crons && /usr/sbin/run-crons )', '']
['May  5 22:41:26 opteron ntpd[3571]: kernel time sync status change 
4001', '']
['May  5 22:41:26 opteron ntpd[3571]: kernel time sync status change 
4001', '']
['May  5 22:41:26 opteron ntpd[3571]: kernel time sync status change 
4001', '']
['May  5 22:41:26 opteron ntpd[3571]: kernel time sync status change 
4001', '']
[/output]

That was with sec_to_wait set at 30

The problem I am having is it will print something whatever sec_to_wait 
is set to even if the file's st_mtime is the same. I want it to only 
prine when the st_mtime has changed. I think I need to update the while 
loop and make old_time = new-time and start over but I need some 
direction to get started, thanks
-david

-- 
Powered by Gentoo GNU/Linux
http://linuxcrazy.com