This is an article used where the subject of the writing is clearly specified in the title. There is a special needs for removing the old PostgreSQL database server instalation so that it can be replaced with the new one. Below are the steps taken in order to accomplish the task :
- Execute the following command :
apt-get remove postgresql*
The ‘*’ sign will automatically add any pattern which has the string of ‘postgresql’ followed with any characters. Below is the actual command execution :
root@hostname:/tmp# apt-get remove postgresql* Reading package lists... Done Building dependency tree Reading state information... Done ... Note, selecting 'postgresql-server-dev-9.1' for glob 'postgresql*' Note, selecting 'postgresql-server-dev-9.2' for glob 'postgresql*' Note, selecting 'postgresql-server-dev-9.3' for glob 'postgresql*' Note, selecting 'postgresql-server-dev-9.4' for glob 'postgresql*' Note, selecting 'postgresql-server-dev-9.5' for glob 'postgresql*' Note, selecting 'postgresql-server-dev-9.6' for glob 'postgresql*' ... Package 'postgresql-server' is not installed, so not removed ... Package 'postgresql-all' is not installed, so not removed Package 'postgresql-client' is not installed, so not removed Package 'postgresql-client-10' is not installed, so not removed Package 'postgresql-client-9.1' is not installed, so not removed Package 'postgresql-client-9.2' is not installed, so not removed Package 'postgresql-client-9.3' is not installed, so not removed Package 'postgresql-client-9.4' is not installed, so not removed Package 'postgresql-client-9.6' is not installed, so not removed ... Package 'postgresql-server-dev-10' is not installed, so not removed Package 'postgresql-server-dev-9.1' is not installed, so not removed Package 'postgresql-server-dev-9.2' is not installed, so not removed Package 'postgresql-server-dev-9.3' is not installed, so not removed Package 'postgresql-server-dev-9.4' is not installed, so not removed Package 'postgresql-server-dev-9.5' is not installed, so not removed Package 'postgresql-server-dev-9.6' is not installed, so not removed Package 'postgresql-server-dev-all' is not installed, so not removed The following packages will be REMOVED: postgresql postgresql-9.5 postgresql-client-9.5 postgresql-client-common postgresql-common postgresql-contrib postgresql-contrib-9.5 0 upgraded, 0 newly installed, 7 to remove and 21 not upgraded. After this operation, 18,4 MB disk space will be freed. Do you want to continue? [Y/n] Y (Reading database ... 404291 files and directories currently installed.) Removing postgresql (9.5+173ubuntu0.1) ... Removing postgresql-contrib (9.5+173ubuntu0.1) ... Removing postgresql-contrib-9.5 (9.5.12-0ubuntu0.16.04) ... update-alternatives: warning: forcing reinstallation of alternative /usr/share/postgresql/9.5/man/man1/postmaster.1.gz because link group postmaster.1.gz is broken Removing postgresql-9.5 (9.5.12-0ubuntu0.16.04) ... Removing postgresql-client-9.5 (9.5.12-0ubuntu0.16.04) ... Removing postgresql-common (173ubuntu0.1) ... Removing 'diversion of /usr/bin/pg_config to /usr/bin/pg_config.libpq-dev by postgresql-common' Removing postgresql-client-common (173ubuntu0.1) ... Processing triggers for man-db (2.7.5-1) ... root@hostname:/tmp# ls
This is another one which is executed to make sure all of the associated packages are fully removed :
root@hostname:/tmp# apt-get --purge remove postgresql postgresql-doc postgresql-common Reading package lists... Done Building dependency tree Reading state information... Done Package 'postgresql' is not installed, so not removed Package 'postgresql-doc' is not installed, so not removed The following packages will be REMOVED: postgresql-common* 0 upgraded, 0 newly installed, 1 to remove and 21 not upgraded. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Y (Reading database ... 403631 files and directories currently installed.) Removing postgresql-common (173ubuntu0.1) ... Purging configuration files for postgresql-common (173ubuntu0.1) ... dpkg: warning: while removing postgresql-common, directory '/var/log/postgresql' not empty so not removed dpkg: warning: while removing postgresql-common, directory '/var/lib/postgresql' not empty so not removed dpkg: warning: while removing postgresql-common, directory '/etc/postgresql' not empty so not removed root@hostname:/tmp# dpkg -l | grep postgres rc postgresql-9.5 9.5.12-0ubuntu0.16.04 amd64 object-relational SQL database, version 9.5 server rc postgresql-client-common 173ubuntu0.1 all manager for multiple PostgreSQL client versions root@hostname:/~#
2. This is another step for the command to be executed :
root@hostname:/~# apt-get --purge remove postgresql-9.5 postgresql-client-common Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED: postgresql-9.5* postgresql-client-common* 0 upgraded, 0 newly installed, 2 to remove and 21 not upgraded. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Y (Reading database ... 403625 files and directories currently installed.) Removing postgresql-9.5 (9.5.12-0ubuntu0.16.04) ... Purging configuration files for postgresql-9.5 (9.5.12-0ubuntu0.16.04) ... Dropping cluster main... Removing postgresql-client-common (173ubuntu0.1) ... Purging configuration files for postgresql-client-common (173ubuntu0.1) ... root@hostname:~#
- Remove the remaining previous installation files which is the library files in the /var/lib/postgresql :
root@hostname:~# rm -rf /var/lib/postgresql/
- Remove the remaining previous installation files which is the log files in the /var/log/postgresl :
root@hostname:/tmp# rm -rf /var/log/postgresql/
- Remove the remaining previous installation files which is located in /etc/postgresql mainly contains configuration files :
root@hostname:/tmp# rm -rf /etc/postgresql/