Customised Error Messages

denzil_cactus · June 14th, 2007, 06:26 AM

Hi all, I ahve written a script which will search for some directories and validate them whether they exist or not and accordingly show the messages(output) like

/usr/bin/denzil => OK
/home/denz/temp => Fail

but the problem is that I need to put a condition to show "Invalid or Insufficient Permissions for the directories which are not accessible to me but they exist like
/home/jessica/temp/perl => No Permission

I have tried the code
my $per = `ls $dir`;

if($per =~ /denied/){

// statement

and
my $per = "ls $dir";
eval($per) or $var =1;

if($var){
//statement

It is showing the default error message everytime ..I need to supress these errors and put my own messages so that it would go to my condition Please help me out

ciderpunx · June 14th, 2007, 10:07 AM

Yuck! Try this:

Code:

my $path = "/path/to/dir";                       # this is the dir you want to open
die ("$path: No permissions") unless (-r $path); # -r $path checks its readable, die if not
opendir(DIR, $path) ||                           # try to open your directory 
          die "Cannot opendir $path: $!";        # if you can't print an error and die
for(sort readdir(DIR)) {                         # loop through the files in the dir, in sorted order
  print "$_\n";                                  # print their names
}
closedir(DIR);                                   # close directory

--
Charlie Harvey's website - linux, perl, java, anarchism and punk rock: http://charlieharvey.org.uk

denzil_cactus · June 15th, 2007, 01:11 AM

well its not working because as soon as it checks for the files which are not accessible gives the
output "the directory does not exist" which is actually because of permission problem...
And my concern is regarding inside any home directory like /home/denzil/temp or
/home/jessica/tmp... Please tell me how to suppress the default error I mean to catch the
default error and put the condition for that

ciderpunx · June 15th, 2007, 10:27 AM

Quote:

quote:
well its not working because as soon as it checks for the files which are not accessible gives the
output "the directory does not exist" which is actually because of permission problem...

erm, just check if the file is readbable in the looop then:

Code:

my $path = "/path/to/dir";                       # this is the dir you want to open
die ("$path: No permissions") unless (-r $path); # -r $path checks its readable, die if not
opendir(DIR, $path) ||                           # try to open your directory 
          die "Cannot opendir $path: $!";        # if you can't print an error and die
for(sort readdir(DIR)) {                         # loop through the files in the dir, in sorted order
  die ("$_: No permissions") unless (-r $_);     # <---- Checks file is readable, dies if it isn't
  print "$_\n";                                  # print their names
}
closedir(DIR);                                   # close directory

Gives me:

Code:

charlie@charlie:~$ su
Password:
charlie:/home/charlie# touch aaa
charlie:/home/charlie# chmod 700 aaa
charlie:/home/charlie# exit
exit
charlie@charlie:~$ ./tmp.pl
.
..
.ICEauthority
.Trash
.Xauthority
Perspectives From The World Social Forum.doc
aaa: No permissions at ./tmp.pl line 9.
charlie@charlie:~$

Quote:

quote:
And my concern is regarding inside any home directory like /home/denzil/temp or
/home/jessica/tmp...

Not sure what you mean here

Quote:

quote:
Please tell me how to suppress the default error I mean to catch the
default error and put the condition for that

I think you're asking me to tell you how to check if a file is readable.
I don't know what a "default error" is. You can say

Code:

if (-r $file) { # if the file is readable
  # do something
}
else { #otherwise
  # do something else
}

hope that helps

--
Charlie Harvey's website - linux, perl, java, anarchism and punk rock: http://charlieharvey.org.uk