File::Copy or system

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

Replies are listed 'Best First'.
Re: File::Copy or system by CountZero (Bishop) on Sep 28, 2011 at 13:38 UTC
If you are fond of the `cp` command and still want to avail yourself of the nice extras provided by File::Copy, just do `use File::Copy qw/cp/;` at the start of your program and the `cp` function is imported into your namespace. With Perl, you can can have your cake and eat it! CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James	[reply] [d/l] [select]
Re: File::Copy or system by Marshall (Canon) on Sep 28, 2011 at 17:32 UTC
File::Copy is a core module. 'Core' means that it is always there. And would be preferred to a system() call even in a pure Unix environment, meaning multi-platform code doesn't matter. yet I think that system has higher readability. I doubt that very much. copy or cp is a very, well used and debugged function and is fast.	[reply]
Re: File::Copy or system by Riales (Hermit) on Sep 28, 2011 at 17:26 UTC
I don't know anything about the security aspect of it, but I was curious about which one was faster, so I ran a benchmark... Copying about 1.5MB: `Benchmark: running File::Copy::cp($a, $b), system('cp', $a, $b) for at + least 3 CPU seconds... File::Copy::cp($a, $b): 4 wallclock secs ( 0.17 usr + 3.18 sys = 3. +35 CPU) @ 339.70/s (n=1138) system('cp', $a, $b): 29 wallclock secs ( 0.13 usr 3.21 sys + 1.43 c +usr 24.26 csys = 29.03 CPU) @ 965.27/s (n=3224)` [download] I'd like to admit that I don't quite know how to parse the results. It looks like the system command incurs a 1.43 cusr and 24.26 csys penalty--what is that?	[reply] [d/l]
Re^2: File::Copy or system by Marshall (Canon) on Oct 03, 2011 at 23:58 UTC
File::Copy will be a native port and will expressed in terms of 'C' calls to the underlying O/S functions. 'C' functions will be called via .DLL's or .so's to do the job without needing a separate processes or programs. The end result is that Perl can copy or move a file faster than the command line shell (like bash, etc) can do it because there is no bash interpreter! (a separate program that has to get started and there are inefficiencies with that...). Your result is not surprising and is expected. A simple Perl program can beat the heck out of MS XCOPY. Well written Perl runs very quickly.	[reply]
Re: File::Copy or system by pvaldes (Chaplain) on Sep 28, 2011 at 22:23 UTC
`In a pure unix environment, is File::Copy::copy($a,$b) preferred to system('cp',$a,$b)?` If what you want is to copy several files to a directory probably not, i.e: `use File::Basename; use File::Copy; use Carp; open my $a, 'myfile.txt'; my ($f,$b,$c) = $fileparse("/home/me/my_dir/my_other_file.txt"); copy($a,$b) or croak; # Oops!` [download]	[reply] [d/l] [select]
Re: File::Copy or system by repellent (Priest) on Sep 30, 2011 at 06:30 UTC
Consider what `system(qw(/bin/cp -rp), $a, $b)` can provide over `File::Copy::copy($a, $b)`. Personally, I prefer the `system` approach.	[reply] [d/l] [select]