Q: Is file readable by all users?

[Troll]

Hi,

Would something like:

if (-r $name) {
: # do nothing
} else {
print "File is not readable...\n";
}

be enough to test if a file is readable by all users?
I'm a little unsure which bit does the -r relate to.

What about if I wanted to test whether the file is readable by the owner's
group but not everyone else?

Cheers

[Troll]

Re: Is file readable by all users?


"Troll" <abuse@microsof t.com> wrote in message
news:MDsbb.1162 24$bo1.40748@ne ws-server.bigpond. net.au...[color=blue]
> Hi,
>
> Would something like:
>
> if (-r $name) {
> : # do nothing
> } else {
> print "File is not readable...\n";
> }
>
> be enough to test if a file is readable by all users?
> I'm a little unsure which bit does the -r relate to.
>
> What about if I wanted to test whether the file is readable by the owner's
> group but not everyone else?
>
> Cheers
>
>[/color]


I had a look at stat and can read the permissions. But what I need to do
then is change the file permissions ONLY if the file is not readable by all
users.
Should I be trying to capture the output of:

$mode = (stat "test.txt") [2];
printf "%0\n", $mode & 07777; # this gives me the original permissions

and then sed-ing it so as to read the last character? If the last char > 3
then the file is readable by all users.
How can I assign the above printf output to a scalar?

Any pointers welcome :)

[Troll]

Re: Is file readable by all users?

*snip*
[color=blue]
> I had a look at stat and can read the permissions. But what I need to do
> then is change the file permissions ONLY if the file is not readable by[/color]
all[color=blue]
> users.
> Should I be trying to capture the output of:
>
> $mode = (stat "test.txt") [2];
> printf "%0\n", $mode & 07777; # this gives me the original permissions
>
> and then sed-ing it so as to read the last character? If the last char > 3
> then the file is readable by all users.
> How can I assign the above printf output to a scalar?
>
> Any pointers welcome :)
>[/color]

Ok, got it.
$permissions = sprintf "%0\n", $mode & 07777;

Silly Q: How do I check if the last digit is > 3? My mind is blank atm...

[Troll]

Re: Is file readable by all users?

*snip*[color=blue][color=green]
> > then the file is readable by all users.
> > How can I assign the above printf output to a scalar?
> >
> > Any pointers welcome :)
> >[/color]
>
> Ok, got it.
> $permissions = sprintf "%0\n", $mode & 07777;
>
> Silly Q: How do I check if the last digit is > 3? My mind is blank atm...
>
>[/color]


Is there something simpler than:
if ($permissions =~ m/^..[4-7]/) {

Thanks.

[Irene Mettias]

Re: Q: Is file readable by all users?

"Troll" <abuse@microsof t.com> wrote in message news:<MDsbb.116 224$bo1.40748@n ews-server.bigpond. net.au>...[color=blue]
> Hi,
>
> Would something like:
>
> if (-r $name) {
> : # do nothing
> } else {
> print "File is not readable...\n";
> }
>
> be enough to test if a file is readable by all users?
> I'm a little unsure which bit does the -r relate to.
>
> What about if I wanted to test whether the file is readable by the owner's
> group but not everyone else?
>
> Cheers[/color]

The -r test only checks if the user running the program can read that
file.
To check if all users can read a file use the 'mode' returned by the
stat() function (3rd returned element).

use Fcntl ':mode';

$mode = (stat($filename ))[2];
$other_read = $mode & S_IROTH;

Check 'perldoc perlfunc' for a full example on how to interpret
'mode'.

Hope that helps.

Irene