So, I needed a function that would compare the timestamp of one file to a directory full of files. If the one first was newer than all the others, the function would continue; otherwise, it would return.

I tried to be clever about this and got the following:

sub chk_snapshot { 
  my $dir=shift; 
 
  return unless -f "$dir/.snapshot"; 
 
  my $ft=(stat("$dir/.snapshot"))[9]; 
  my @fts=map { (stat($_))[9] } grep -f $_,($0,glob "$dir/*"); 
  
  ## return if .snapshot is older than any 
  for my $x (@fts) { 
    return if $x > $ft; 
  } 
 
  warn "snapshot is newer"; 
  
  snarf_file("$dir/.snapshot"); 
}

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What I wanted to do is get rid of the for my $x (@fts) construct and somehow combine it with the map statement (getting rid of the @fts variable at the same time). I had tried something like 
return if map { (stat($_))[9] > $ft } grep -f $_,($0,glob "$dir/*");

[download]
But that didn't work because map returns (in this case) an array of undef's, not an empty array; so the return in that construct is always executed.

So my question is, does anyone know how to achieve the goal of gathering the filestamps AND checking them in a single line (like my non-functional return if map ...)?

TIA!

In reply to Clever timestamp comparison by mr.nick

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