Hi, I have a couple of perl programmatical problems which due to my lack of indepth knowledge of Perl I'm struggling to find a solution for.
Here in a nutshell is what I wish to achieve
Note that the perlscript runs as userA who does not own the target directories these are owned by UserB

# get target directory path (this will change through each iteration o
+f the utility)
$destination = "/abc/def/ghi/jkl" # this is a directory

`sudo -u UserB setfacl ....set group level perms on $destination` 

# is target direcory readable now
-r $destination
or
$newdestination = traverse backwards to next level (e.g. "/abc/def/ghi
+") 
run the sudo command to set the perms on $newdestination

Do the read test again on the original $destination
If successful finish 
otherwise
traverse back up the directory chain again and redo the setfacl and re
+ad test
[download]

Note that UserB is the owner of the directory tree, hence the reason the setfacl is run as UserB.
A further problem I have is with the gid of UserA. At a unix level UserA has the group that UserB is setting the file perms for BUT it's not the primary group of UserA.
The other question is how do I change the gid of UserA so that the test above will be successful once the correct perms have been set down the directory path by UserB ?
This may sound overly complicated but unfortunately this is due to the security of the arena I'm working in. I can manually achieve the desired result but can't seem to translate this into a perl.
Any ideas on how the above could be achieved would be welcome.