Monitor folder for new files using unix ksh shell

Question

I've been Googling and Overflowing for a bit and couldn't find anything usable.

I need a script that monitors a public folder and triggers on new file creation and then moves the files to a private location.

I have a samba shared folder /exam/ple/ on unix mapped to X:\ on windows. On certain actions, txt files are written to the share. I want to kidnap any txt file that appears in the folder and place it into a private folder /pri/vate on unix. After that file is moved, I want to trigger a separate perl script.

EDIT Still waiting to see a shell script if anyone has any ideas... something that will monitor for new files and then run something like:

#!/bin/ksh
mv -f /exam/ple/*.txt /pri/vate

Answer 1

I don't use ksh but here's how i do it with sh. I'm sure it's easily adapted to ksh.

#!/bin/sh
trap 'rm .newer' 0
touch .newer
while true; do
  (($(find /exam/ple -maxdepth 1 -newer .newer -type f -name '*.txt' -print \
      -exec mv {} /pri/vate \; | wc -l))) && found-some.pl &
  touch .newer
  sleep 10
done

Answer 2

If I understand correctly, you just want something like this?

#!/usr/bin/perl

use strict;
use warnings;

use File::Copy

my $poll_cycle = 5;
my $dest_dir = "/pri/vate";

while (1) {
    sleep $poll_cycle;

    my $dirname = '/exam/ple';

    opendir my $dh, $dirname 
        or die "Can't open directory '$dirname' for reading: $!";

    my @files = readdir $dh;
    closedir $dh;

    if ( grep( !/^[.][.]?$/, @files ) > 0 ) {
        print "Dir is not empty\n";

        foreach my $target (@files) {
            # Move file
            move("$dirname/$target", "$dest_dir/$target");

            # Trigger external Perl script
            system('./my_script.pl');
    }
}

Answer 3

This will result in a fair bit of io - stat() calls and the like. If you want rapid notification without the runtime overhead (but more upfront effort), take a look at FAM/dnotify: link text or link text

Answer 4

$ python autocmd.py /exam/ple .txt,.html /pri/vate some_script.pl

Advantages:

• easier to install than incron due to pyinotify is pure Python
• event-driven -- less impact than the perl script

autocmd.py:

#!/usr/bin/env python
"""autocmd.py 

Adopted from autocompile.py [1] example.

[1] http://git.dbzteam.org/pyinotify/tree/examples/autocompile.py

Dependencies:

Linux, Python, pyinotify
"""
import os, shutil, subprocess, sys

import pyinotify
from pyinotify import log

class Handler(pyinotify.ProcessEvent):
    def my_init(self, **kwargs):
        self.__dict__.update(kwargs)

    def process_IN_CLOSE_WRITE(self, event):
        # file was closed, ready to move it
        if event.dir or os.path.splitext(event.name)[1] not in self.extensions:
           # directory or file with uninteresting extension
           return # do nothing

        try:
            log.debug('==> moving %s' % event.name)
            shutil.move(event.pathname, os.path.join(self.destdir, event.name))
            cmd = self.cmd + [event.name]
            log.debug("==> calling %s in %s" % (cmd, self.destdir))
            subprocess.call(cmd, cwd=self.destdir)
        except (IOError, OSError, shutil.Error), e:
            log.error(e)

    def process_default(self, event):
        pass


def mainloop(path, handler):
    wm = pyinotify.WatchManager()
    notifier = pyinotify.Notifier(wm, default_proc_fun=handler)
    wm.add_watch(path, pyinotify.ALL_EVENTS, rec=True, auto_add=True)
    log.debug('==> Start monitoring %s (type c^c to exit)' % path)
    notifier.loop()


if __name__ == '__main__':
    if len(sys.argv) < 5:
       print >> sys.stderr, "USAGE: %s dir ext[,ext].. destdir cmd [args].." % (
           os.path.basename(sys.argv[0]),)
       sys.exit(2)

    path = sys.argv[1] # dir to monitor
    extensions = set(sys.argv[2].split(','))
    destdir = sys.argv[3]
    cmd = sys.argv[4:]

    log.setLevel(10) # verbose

    # Blocks monitoring
    mainloop(path, Handler(path=path, destdir=destdir, cmd=cmd,
                           extensions=extensions))

Answer 5

Check incron. It seems to do exactly what you need.

Answer 6

File::ChangeNotify allows you to monitor files and directories for changes.

https://metacpan.org/pod/File::ChangeNotify