how to create a script from a perl script which will use bash features to copy a directory structure - perl

Question

hi i have written a perl script which copies all the entire directory structure from source to destination and then i had to create a restore script from the perl script which will undo what the perl script has done that is create a script(shell) which can use bash features to restore the contents from destination back to source i m struggling to find the correct function or command which can copy recursively (not an requirement) but i want exactly the same structure as it was before
Below is the way i m trying to create a file called restore to do the restoration process
i m particularly looking for algorithm.
Also restore will restore the structure to a command line directory input if it is supplied if not You can assume the default input supplied to perl script
$source
$target
in this case we would wanna copy from target to source
So we have two different parts in one script.
1 which will copy from source to destination.
2 it will create a script file which will undo what part 1 has done
i hope this makes it very clear
unless(open FILE, '>'."$source/$file")
{
# Die with error message
# if we can't open it.
die "\nUnable to create $file\n";
}
# Write some text to the file.
print FILE "#!/bin/sh\n";
print FILE "$1=$target;\n";
print FILE "cp -r \n";
# close the file.
close FILE;
# here we change the permissions of the file
chmod 0755, "$source/$file";
The last problem i have is i couldn't get $1 in my restore file as it refers to a some variable in perl
but i need this for getting command line input when i run restore as $0 = ./restore $1=/home/xubuntu/User

Answer 1

First off, the standard way in Perl for doing this:
unless(open FILE, '>'."$source/$file") {
die "\nUnable to create $file\n";
}
is to use the or statement:
open my $file_fh, ">", "$source/$file"
or die "Unable to create "$file"";
It's just easier to understand.
A more modern way would be use autodie; which will handle all IO problems when opening or writing to files.
use strict;
use warnings;
use autodie;
open my $file_fh, '>', "$source/$file";
You should look at the Perl Modules File::Find, File::Basename, and File::Copy for copying files and directories:
use File::Find;
use File::Basename;
my #file_list;
find ( sub {
return unless -f;
push #file_list, $File::Find::name;
},
$directory );
Now, #file_list will contain all the files in $directory.
for my $file ( #file_list ) {
my $directory = dirname $file;
mkdir $directory unless -d $directory;
copy $file, ...;
}
Note that autodie will also terminate your program if the mkdir or copy commands fail.
I didn't fill in the copy command because where you want to copy and how may differ. Also you might prefer use File::Copy qw(cp); and then use cp instead of copy in your program. The copy command will create a file with default permissions while the cp command will copy the permissions.
You didn't explain why you wanted a bash shell command. I suspect you wanted to use it for the directory copy, but you can do that in Perl anyway. If you still need to create a shell script, the easiest way is via the :
print {$file_fh} << END_OF_SHELL_SCRIPT;
Your shell script goes here
and it can contain as many lines as you need.
Since there are no quotes around `END_OF_SHELL_SCRIPT`,
Perl variables will be interpolated
This is the last line. The END_OF_SHELL_SCRIPT marks the end
END_OF_SHELL_SCRIPT
close $file_fh;
See Here-docs in Perldoc.

Answer 2

First, I see that you want to make a copy-script - because if you only need to copy files, you can use:
system("cp -r /sourcepath /targetpath");
Second, if you need to copy subfolders, you can use -r switch, can't you?