rpm is present, but nothing is installed...

	root@redbox:~# rpm
	RPM version 4.4.1
	Copyright (C) 1998-2002 - Red Hat, Inc.
	This program may be freely redistributed under the terms of the GNU GPL

	root@redbox:~# rpm
	(no reponse because no packages installed)

This is one of the proper Debian package managers (the lowest-level; the other one is apt)...

	root@redbox:~# dpkg -l
	Desired=Unknown/Install/Remove/Purge/Hold
	| Status=Not/Installed/Config-files/Unpacked/Failed-config/Half-installed
	|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
	||/ Name           Version        Description
	+++-==============-==============-============================================
	ii  acpi           0.09-1         displays information on ACPI devices
	(many packages listed...)

	root@redbox:/etc# ll | grep dpkg
	drwxr-xr-x  3 root   root        96 2006-06-07 15:01 dpkg
	-rw-r--r--  1 root   root       470 2005-09-29 11:40 nsswitch.conf.dpkg-dist
	-rw-r--r--  1 root   root       552 2006-05-12 11:42 pam.conf.dpkg-dist

Compare with host taliesin...

	russ@taliesin:~> ll /etc | grep dpkg
	(nothing)

To install...

	# dpkg --install package-path
	# dpkg -i package-path

To list installed packages...

	# dpkg -list package-name-pattern
	# dpkg -l package-name-pattern

Unused by the install script, this command lists the files installed to the system by the package:

	# dpkg -listfiles package-name
	# dpkg -L package-name

To upgrade...

	# dpkg --update-avail package-path

There is also dpkg -A package-path which I was using, but according to the man page, that might not be as useful as the one listed here.

To uninstall (remove)...

	# dpkg -remove package-name
	# dpkg -r package-name

I heard it asserted by someone in the vim newsgroup that the only command that truly uninstalls a package is. This is because the remove command doesn’t remove the configuration files.

	# dpkg --purge package-name
	# dpkg -P package-name

Lists all packages containing .

	# dpkg - l | grep 

Show where everything is installed.

	# dpkg -L 

Ubuntu/Debian package manager. For a long time, I called this "Aptitude" thinking that apt was just short of that word. After a decade of believing that, I discovered during a presentation that it stands for advanced packaging tool, though Aptitude does exist in relation to apt. The relation is simply that Aptitude is a front-end with user interace to the advanced packaging tool's command-line interface. Also, though I've never seen proof of this, Aptitude at some point extended its coverage to Red Hat packaing (RPM). Simply put, I mistook what Aptitude is and I don't think I've ever actually used it. I've only ever used apt.

	russ@taliesin:~> apt-cache search element
	russ@taliesin:~> apt-get   install package-name

Sometimes, it's useful to remove apt lists and rebuild them. sudo/root access is needed: Do this:

	# sudo bash
	$ cd /var/lib/apt
	$ mv lists lists.old
	$ apt-get update

Look also at the output from

	$ apt-key list

Block Ubuntu from ever updating Cassandra. This is because I'm working on a plug-in that only works with a, specific version of Cassandra.

# apt-mark hold cassandra
cassandra set on hold.

I downloaded MongoDB to repair the post-install script. I'm going to do this and keep it around for use instead of trying to get it from apt-get.

1. Download the Debian package—without installing it.

   This is especially easy if you've got a place where it's already downloaded. Check the path /var/cache/apt/archives for the package. Otherwise (and I haven't done this), you might be able to get it via this command, which typically won't work if you do happen already to have it:

       $ sudo apt-get --download-only mongodb-10gen
   

2. Next, copy the package to a nice place where you can work on it, e.g.: /home/user/Downloads/mongodb. Make that your current working directory.
3. Create a new subdirectory where the package contents will go, e.g.: mongodb-package. You should now see the following in /home/user/Downloads/mongodb

       ~/Downloads/mongodb $ ll
       drwxr-xr-x 3 russ russ     4096 Jul 29 14:21 .
       drwxr-xr-x 5 russ russ     4096 Jul 29 14:16 ..
       -rw-r--r-- 1 russ russ 87724864 Jul 29 14:21 mongodb-10gen_2.4.5_amd64.deb
       drwxr-xr-x 6 russ russ     4096 Jul 29 14:01 mongodb-package
   

4. Then, extract the package to it:

       ~/Downloads/mongodb $ dpkg-deb -x mongodb-10gen_2.4.5_amd64.deb ./mongodb-package
   

   You should now see the entire package contents extracted in your subdirectory:

       ~/Downloads/mongodb $ tree
       .
       |-- mongodb-10gen_2.4.5_amd64.deb
       `-- mongodb-package
           |-- DEBIAN
           |   |-- conffiles
           |   |-- control
           |   |-- md5sums
           |   |-- postinst
           |   |-- postrm
           |   |-- preinst
           |   `-- prerm
           |-- etc
           |   |-- init
           |   |   `-- mongodb.conf
           |   |-- init.d
           |   |   `-- mongodb -> /lib/init/upstart-job
           |   `-- mongodb.conf
           |-- usr
           |   |-- bin
           |   |   |-- bsondump
           |   |   |-- mongo
           |   |   |-- mongod
           |   |   |-- mongodump
           |   |   |-- mongoexport
           |   |   |-- mongofiles
           |   |   |-- mongoimport
           |   |   |-- mongooplog
           |   |   |-- mongoperf
           |   |   |-- mongorestore
           |   |   |-- mongos
           |   |   |-- mongostat
           |   |   `-- mongotop
           |   |-- sbin
           |   `-- share
           |       |-- doc
           |       |   `-- mongodb-10gen
           |       |       |-- changelog.gz
           |       |       `-- copyright
           |       |-- lintian
           |       |   `-- overrides
           |       |       `-- mongodb-10gen
           |       `-- man
           |           `-- man1
           |               |-- bsondump.1.gz
           |               |-- mongo.1.gz
           |               |-- mongod.1.gz
           |               |-- mongodump.1.gz
           |               |-- mongoexport.1.gz
           |               |-- mongofiles.1.gz
           |               |-- mongoimport.1.gz
           |               |-- mongooplog.1.gz
           |               |-- mongoperf.1.gz
           |               |-- mongorestore.1.gz
           |               |-- mongos.1.gz
           |               |-- mongosniff.1.gz
           |               |-- mongostat.1.gz
           |               `-- mongotop.1.gz
           `-- var
               `-- lib
                   `-- mongodb
   
       18 directories, 41 files
   

5. Next, modify what's bugging you. In my case, this was the postinst script.
6. Finally, reassemble the package:

   ~/Downloads/mongodb # dpkg-deb -b ./mongodb-package/ mongodb-10gen_2.4.5_amd64.deb
   dpkg-deb: building package `mongodb-10gen' in `mongodb-10gen_2.4.5_amd64.deb'.
   

To examine the reassembly and/or compare it to the original, you can use Nautilus (the GUI file system explorer) by finding the new (and old) package, right-clicking on it and choosing Open with Archive Manager. Then, if you want to see the contents of a text file, right-click the text file and choose gvim (etc.) to see it. You can't modify them there since everything is read-only.

The resulting package should install without trouble anywhere you copy it using the Debian package manager (rather than apt-get):

    $ sudo dpkg -i mongodb-10gen_2.4.5_amd64.deb

The package problem I fixed...

For my own record: what I did to the postinst script 'cause I'll likely have to do it again.

Basically, the problem is that this script greps /etc/passwd to see if user mongodb already exists and if it doesn't, tries to create it. This doesn't work if your server's managed with LDAP and happens already to define user mongodb. Don't know why powers that be decided to create such a user, but it's in LDAP and not in /etc/passwd. adduser doesn't work just on what's in or not in that local file. The presence of this user makes me have to fix this script and run dpkg by hand everywhere I wish to install. Otherwise, apt-get install fails because dpkg fails. No automatic updates either.

I commented out the first line here in italics and added the line in bold, then rebuilt the package which worked.

    21 case "$1" in
    22     configure)
    23     # create a mongodb group and user
    24         #if ! grep -q mongodb /etc/passwd; then
    25        if ! id mongodb ; then
    26         adduser --system --no-create-home mongodb
    27         addgroup --system mongodb
    28         adduser mongodb mongodb
    29         fi