/usr/lib/postgresql/9.4/bin/pg_ctl: No such file or directory
postgres@pangaea:/usr/lib/postgresql/9.4/bin$ ls -al total 4008 drwxr-xr-x 2 root root 4096 Feb 9 16:17 . drwxr-xr-x 3 root root 4096 Feb 9 16:17 .. -rwxr-xr-x 1 root root 68128 Nov 16 06:53 clusterdb -rwxr-xr-x 1 root root 68192 Nov 16 06:53 createdb -rwxr-xr-x 1 root root 63920 Nov 16 06:53 createlang -rwxr-xr-x 1 root root 72672 Nov 16 06:53 createuser -rwxr-xr-x 1 root root 63936 Nov 16 06:53 dropdb -rwxr-xr-x 1 root root 63920 Nov 16 06:53 droplang -rwxr-xr-x 1 root root 63904 Nov 16 06:53 dropuser -rwxr-xr-x 1 root root 68416 Nov 16 06:53 pg_basebackup -rwxr-xr-x 1 root root 351904 Nov 16 06:53 pg_dump -rwxr-xr-x 1 root root 2186504 Nov 16 06:53 pg_dumpall -rwxr-xr-x 1 root root 30992 Nov 16 06:53 pg_isready -rwxr-xr-x 1 root root 47600 Nov 16 06:53 pg_receivexlog -rwxr-xr-x 1 root root 51928 Nov 16 06:53 pg_recvlogical -rwxr-xr-x 1 root root 154944 Nov 16 06:53 pg_restore -rwxr-xr-x 1 root root 515320 Nov 16 06:53 psql -rwxr-xr-x 1 root root 68160 Nov 16 06:53 reindexdb -rwxr-xr-x 1 root root 72384 Nov 16 06:53 vacuumdb
As I mentioned, this Debian package removes pg_ctl from the bin directory and instead attempts to wrap the pg_ctl functionality in a perl script so that the PG process is integrated with systemd. I really wish they hadn’t, and it’s part of the reason I’m where I’m at.
pg_ctl is normally present in /usr/lib/postgresql/<version>/bin on a debian system. If that is gone, somebody removed it, or you didn't install the "postgresql-9.4" package which provides it. On a 9.4 system:
You could try reinstalling the postgresql-9.4 package and see if it comes back. The rest of the binaries in that directory seems to be from postgresql-9.4-client though -- have you actually by mistake uninstalled the server package completely?
As in, that directory is supposed to have the "postgres" binary which is the database server and it's not there. So there is no wonder it's not starting...