How to verify mount point

Mery84 has asked for the wisdom of the Perl Monks concerning the following question:

Hi!
I need help with perform test on mount points.
I need to be sure that $usbdev is mounted on $usbmount if not - do some bunch of code like write warning to logfile and mail me.

$usbdev = "/dev/sde1/";
$usbmount = "/media/usb/";

system("mount $usbdev $usbmount");

Here should be test
[download]

When I do mount how to check is this operation is successful and files copied to $usbmount are copied to usb stick? If $usbdev isn`t mounted the copy part of script stil works, files are stored on / partition where /media dir is placed.
Simple check:

if (! -e "$usbmount") {
print "error \n";
}
[download]

fails - error is returned always no matter is usb stick mounted or not, is it pluged in or not.

Comment on How to verify mount point Select or Download Code

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Re: How to verify mount point by Eliya (Vicar) on Mar 23, 2012 at 15:57 UTC
Maybe you want to check the output of the `mount` command (called without args), or the contents of `/proc/mounts`, if you have a system with a proc file system.	[reply] [d/l] [select]
Re: How to verify mount point by Tux (Canon) on Mar 23, 2012 at 16:03 UTC
Sounds like a job for Sys::Filesystem. Enjoy, Have FUN! H.Merijn	[reply]
Re: How to verify mount point by moritz (Cardinal) on Mar 23, 2012 at 16:07 UTC
The system docs tell you how to query the return value, and mount returns 0 for successful mounts. Perl 6 - second systems done right	[reply]
Re: How to verify mount point by JavaFan (Canon) on Mar 23, 2012 at 16:24 UTC
Assuming you aren't using the program as root, one way of doing it is to give `/media/usb` permission 755. Any attempt to write to the directory will fail if the device hasn't been mounted. You'll have to add `user` to the list of options in `/etc/fstab` for the device. Otherwise, you can just parse the output of `mount`, or look in `/proc/mounts` or in `/etc/mtab`.	[reply] [d/l] [select]
Re: How to verify mount point by reisinge (Hermit) on Mar 23, 2012 at 19:02 UTC
You could use `unless` control structure to execute the code in the block just upon successful mount: `use strict; use warnings; use File::Copy; my $usbdev = "/dev/sdb1/"; my $usbmount = "/media/usb/"; my @files = qw( file1 file2 file3 ); # or read from the filesystem usi +ng a glob or directory handle unless ( system "mount $usbdev $usbmount" ) { # Return was zero - meaning success for my $file (@files) { copy($file,$usbmount) or warn "Failed to copy $file: $!\n"; } ! system "umount $usbmount" or die "Can't umount $usbmount\n"; }` [download] Have a nice day, j	[reply] [d/l] [select]
Re^2: How to verify mount point by Mery84 (Novice) on Mar 26, 2012 at 07:55 UTC
Many thanks for this example - this is short, simple and works excellent. Thanks to all of you Monks for your support :).	[reply]
Re: How to verify mount point by salva (Canon) on Mar 23, 2012 at 22:51 UTC
On Linux you can also use Linux::Proc::Mountinfo.	[reply]