Comment 10 for bug 1360693

I became the output below.

I did an additional test, follow your advice, and add a cover. I did it with the editor and add simply the pic inside the epub as cover and save that file. Then I import the updated epub. This way it works. It seems that with Linux the procedure seems to be different (I have in our German forum a person with the same problem).

armin@ubuntu:~/Schreibtisch$ echo run\nbt | gdb --args /opt/calibre/ebook-meta db030-473.epub --get-cover cover.jpg
GNU gdb (Ubuntu 7.7-0ubuntu3.1) 7.7
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /opt/calibre/ebook-meta...(no debugging symbols found)...done.
(gdb) Undefined command: "runnbt". Try "help".
(gdb) quit
armin@ubuntu:~/Schreibtisch$ echo 'run\nbt' | gdb --args /opt/calibre/ebook-meta db030-473.epub --get-cover x.jpg
GNU gdb (Ubuntu 7.7-0ubuntu3.1) 7.7
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /opt/calibre/ebook-meta...(no debugging symbols found)...done.
(gdb) Starting program: /opt/calibre/ebook-meta \nbt
process 5652 is executing new program: /opt/calibre/bin/ebook-meta
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Traceback (most recent call last):
  File "site.py", line 51, in main
  File "site-packages/calibre/ebooks/metadata/cli.py", line 168, in main
IOError: [Errno 2] Datei oder Verzeichnis nicht gefunden: u'nbt'
[Inferior 1 (process 5652) exited with code 01]
(gdb) quit
armin@ubuntu:~/Schreibtisch$