Question

I am attempting to create a top-level script that will call about 35+ other scripts that will each seek to modify/create text files. Not the best approach of doing things and not the most fun either, but needs must.

I call each of these scripts with the ‘system’ command, but I would like to know of methods to find out which files have been created/modified by each script that was called.

The most non-intrusive way is to simply note the timestamps on all files in the work directory before and after running the sub-script, but I worry that might not be robust enough.

So I am wondering whether there is a module/method in Perl which I can quickly put into all the sub-scripts that will catch all file operations and pass that onto the calling script as a return value of some sort?

All help much appreciated and alternative ideas very welcome indeed!

cheers

Answer 1

Like a’r suggested, I would be tempted to use strace. Replace calls to system() with calls to this wrapper:

use File::Temp qw/tempfile/;

# ...

sub sys { # a wrapper for system()
  my ($fh, $filename) = tempfile();
  my $st = system("strace", "-o", $filename, "-eopen", @_);

  # report files used by the script -- customize as needed
  print STDERR "files accessed by $_[0]:\n";
  while (<$fh>) { print STDERR; }

  return $st;
}

Then you only modify the parent script instead of all of the child scripts.

The -eopen parameter to strace filters out only the open calls. This will also catch calls to fopen (which is a C library routine and not a system call.)