Re: Linux file permission for COPY TO SQL command

Actually server and client are installed on the same machine.

The file (real file) permissions are as follows:

-rwxrwxrwx+ 1 kaj kaj 2 Oct 27 22:36 fd/fdo.txt

The directory permissions are as follows:

drwxrwxrwx+  4 kaj kaj     4096 Oct 27 22:36 fd

The SQL command which tries to write to the file is this:

copy (select key from xcg where add=false) to '/home/kaj/fd/fdo.txt';


Pozdrawiam
Krzysztof Jasieński

On 10/29/25 5:12 PM, Roland Müller wrote:
>
> Hello,
>
>
> COPY TO  stores the output into a file on the server rather than in 
> your local where client is running.
>
>
> Spaces in the file name are actually no issue:
>
> $ psql -h 172.17.0.2 -U postgres -c "COPY (SELECT * FROM pg_class) TO 
> '/var/tmp/pg_class.       OUT  x'"
> Password for user postgres:
> COPY 420
>
> ... but the output file is on the server - in this example inside a 
> docker container
>
> postgres@7680e256387f:~$ ls -ltr /var/tmp
> total 208
> ...
> -rw-r--r-- 1 postgres postgres 49291 Oct 29 16:08 'pg_class.    OUT  x'
>
>
> Copying to client side can be done with \copy (<query or table>) to 
> '<output file>';
>
>
> BR/Pozdrawiam,
>
> Roland
>
>
> On 10/29/25 01:03, Rob Sargent wrote:
>>
>>
>>> On Oct 28, 2025, at 9:39 AM, Krzysztof <kj@limes.com.pl> wrote:
>>>
>>> 
>>>
>>> I try to use COPY TO command to copy results of a SELECT but I get 
>>> this message:
>>>
>>> ERROR:  could not open file "a file" for writing: Permission denied
>>>
>>
>> Is there really a space in the actual file name. That might get 
>> tricky. You’re suggesting the file already exists: is that true? 
>> Directory permissions?
>>>
>>> User, group and other are granted full permission to this file. What 
>>> should I do more to get this working?
>>>
>>> -- 
>>> Pozdrawiam
>>> Krzysztof Jasieński