Question

I created 10000 files – my default limit was ” ulimit -n 1024″ – I expected following script to fail with a message like “Too many files open” , but it didn’t fail. (/tmp/files has 10000 files)

Any thoughts on where am i going wrong?

import os
listfiles=os.listdir('/tmp/files')
count=0
f=''
for file in listfiles:
        fn=f+str(count)
        fn=open(file,'w')
        fn.write('hello')
        print 'file=',file
        count=count+1

print count

Answer 1

for file in listfiles:
        fn = f+str(count)    # what is this supposed to do?
        fn = open(file,'w')  # old file handle gets garbage collected and closed
        fn.write('hello')
        print 'file=',file
        count = count + 1

Every time you rebind fn the previous file gets closed. It’s possible that in jython for example the file doesn’t get closed immediately, but it very likely will still be garbarge collected and closed before you exceed the 1024 file limit

Try storing the file objects in a list like this:

import os
listfiles = os.listdir('/tmp/files')
count = 0
f = ''
fn = []
for file in listfiles:
        fn.append(open(file,'w'))
        fn[-1].write('hello')
        print 'file=',file
        count = count + 1

print count