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

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