How to get the number of open file descriptors?

Question

How to find number of files opened by my Perl program? Of course, I could use something like

scalar( my @a = glob "/proc/$$/fd/*" );

but it looks a bit hacky... I should have overlooked something very simple.

score 1 · Answer 1 · answered Nov 10 '12 at 22:30

You can scan all possible file handles from 0 to to getrlimit(RLIMIT_NOFILE) using either fstat() call or fcntl(fd, F_GETFL) call.

However, using any of these will be significantly slower than simply looking at /proc/self/fd/*. And, they still depend on some Linux'isms and do not make your program portable.

score 0 · Accepted Answer · edited May 23 '17 at 10:24

0

There is a similar question to that here How to find open global filehandles in a perl program

You will need to change it a bit to suit your requirements

edited May 23 '17 at 10:24

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answered Nov 10 '12 at 06:38

Ahmad

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The selected answer there has the code from my question... Looks like case closed. – Dallaylaen Nov 10 '12 at 07:13
Glad to be of some assistance. – Ahmad Nov 10 '12 at 07:14

score -1 · Answer 3 · answered Nov 10 '12 at 07:16

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you could use lsof to for that eg. lsof /|wc -l should work fine

answered Nov 10 '12 at 07:16

Saddam Abu Ghaida

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AFAIK `lsof` uses /proc/*/fd internally, so it's generally the same... Oh and I need files open by _this_ process, not everyone else. – Dallaylaen Nov 10 '12 at 07:36

How to get the number of open file descriptors?

3 Answers3