[OS X TeX] [MacTeX 2015] Cannot open Ghostscript for piped input

[Herbert Schulz]

> On Dec 12, 2015, at 1:37 PM, Don Green Dragon <fergdc at Shaw.ca> wrote:
> 
> Hi Herb,
> 
> Have been following the thread and after reading
> 
> On 10Dec2015, at 3:36 PM, Herb Schulz <herbs at wideopenwest.com> wrote:
> 
>> sudo chown root:wheel /usr/local/bin
> 
> I gave the command above and this is what followed (between the hashed lines)

Howdy,

Very dramatic! Were you having the same problem as that person; not being able to run Ghostscript (gs)?

I don't know if you even needed to do that at all. That person's /usr/local/bin directory was owned by user `504' (that was the UID for that user) with group `wheel'; it should have been owned by `root' with group `wheel' and that command fixed that.

Take a look at the results of 

ls -alF /usr/local

and the line for bin should look something like

drwxr-xr-x  432 root  wheel  14688 Sep 26 06:11 bin/

(that 14688 could be very different for different users). That shows that the owner is `root' and group is `wheel'. The drwxr-xr-x in front show that it is a directory (d), the following `rwx' mean that the owner (root) can read/write/execute bin (`execute' means that the contents of the directory are visible) while the following `r-x' mean that members of the group (wheel) can read/execute (again, execute means look at the contents of the directory but cannot write to that directory and the final `r-x' refers to everyone else.

The original person couldn't execute gs because he wasn't allowed to even look in that directory; the permission bits were originally drwx------ so that only the owner (originally user 504, with root after that command I gave) could even look inside that directory to access what's in it. (Well, root can look inside any directory so even when it was owned by 504 root could see inside it.)

Hope that explains things.

PS: the original poster understood what was being shown with that 

ls -alF /usr/local

command and changed the permissions from drwx------ to drwxr-xr-x before I told hom to change the owner from 504 to root.

Good Luck,

Herb Schulz
(herbs at wideopenwest dot com)