[PLUTO-help] curiosità su apt-get

[Hugh Hartmann]

Ciao Lorenzo,
e un cordiale saluto a tutti i partecipanti alla lista pluto-help ...

On Mon, Jun 20, 2005 at 10:11:53AM +0200, Lorenzo Luilli wrote:
> Ciao a tutti,
> si avvicina l'estate e noi insegnanti precari siamo a spasso a  
> goderci la disoccupazione.... :-)

Beh, "Mal comune mezzo gaudio" .... :-)

Devo dire che siamo ormai in tanti e, se continuera' cosi, la lista
tendera' ad aumentare .... :-)

> così, col cervello libero da lezioni e interrogazioni, mi è venuta  
> una curiosità sulla mia amata Debianuccia che non sono riuscito a  
> sbrogliare, perciò ve la giro:
 
> Ho notato che alcuni consigliano la sequenza
 
> apt-get update  apt-get upgrade  apt-get dist-upgrade
> altri saltano direttamente al dist-upgrade,
> altri usano l'opzione -u:
> apt-get -u dist-upgrade

Allora, direttamente dalla pagina di manuale:

---------

NAME
       apt-get  -  APT  package  handling utility -- command-line
       interface


SYNOPSIS
       apt-get [options] [command] [package ...]


DESCRIPTION
       apt-get is the command-line tool  for  handling  packages,
       and may be considered the user´s "back-end" to apt(8).

       command is one of:

       o      update

       o      upgrade

       o      dist-upgrade

[...]
       

       update 
	      update  is  used  to  resynchronize   the   package
              overview files from their sources. The overviews of
              available packages are fetched from the location(s)
              specified  in  /etc/apt/sources.list.  For example,
              when using a Debian archive, this command retrieves
              and  scans  the Packages.gz files, so that informa­
              tion about new and updated packages  is  available.
              An  update  should  always  be  performed before an
              upgrade dist-upgrade.  Please  be  aware  that  the
              overall  progress  meter  will  be incorrect as the
              size of  the  package  files  cannot  be  known  in
              advance.

[...]

       upgrade
              upgrade  is  used to install the newest versions of
              all packages currently installed on the system from
              the  sources  enumerated  in /etc/apt/sources.list.
              Packages  currently  installed  with  new  versions
              available are retrieved and upgraded; under no cir­
              cumstances   are   currently   installed   packages
              removed,   or   packages   not   already  installed
              retrieved and installed. New versions of  currently
              installed  packages that cannot be upgraded without
              changing the install status of another package will
              be left at their current version. An update must be
              performed first so that apt-get knows that new ver­
              sions of packages are available.

[...]

       dist-upgrade
              dist-upgrade,in addition to performing the function
              of upgrade,  also  intelligently  handles  changing
              dependencies with new versions of packages; apt-get
              has a "smart" conflict resolution  system,  and  it
              will attempt to upgrade the most important packages
              at the expense of less important ones if necessary.
              The  /etc/apt/sources.list  file contains a list of
              locations from which to  retrieve  desired  package
              files.

[...]

OPTIONS
       All  command  line options may be set using the configura­
       tion file, the  descriptions  indicate  the  configuration
       option  to  set.  For boolean options you can override the
       config file by using something like -f-, --no-f, -f=no  or
       several other variations.


       -d, --download-only
              Download  only;  package  files are only retrieved,
              not unpacked  or  installed.   Configuration  Item:
              APT::Get::Download-Only.


       -f, --fix-broken
              Fix; attempt to correct a system with broken depen­
              dencies in  place.  This  option,  when  used  with
              install/remove, can omit any packages to permit APT
              to deduce a likely soltion. Any  Package  that  are
              specified  must  completly correct the problem. The
              option is sometimes necessary when running APT  for
              the  first  time;  APT itself does not allow broken
              package dependencies to exist on a  system.  It  is
              possible  that  a system´s dependency structure can
              be so corrupt as  to  require  manual  intervention
              (which usually means using dselect or dpkg --remove
              to eliminate some of the offending  packages).  Use
              of  this  option  together  with  -m may produce an
              error  in  some  situations.  Configuration   Item:
              APT::Get::Fix-Broken.


       -h, --help
              Help; display a helpful usage message and exits.


       -v, --version
              Show the program version.


[...]
       -u, --show-upgraded
              Show upgraded packages; Print out  a  list  of  all
              packages  that  are  to  be upgraded. Configuration
              Item: APT::Get::Show-Upgraded.


       -b, --compile, --build
              Compile source  packages  after  downloading  them.

[...]

FILES
       o      /etc/apt/sources.list  locations  to fetch packages
              from

       o      /var/cache/apt/archives/ storage area for retrieved
              package files

       o      /var/cache/apt/archives/partial/  storage  area for
              package files in transit

       o      /var/state/apt/lists/  storage   area   for   state
              information  for each package resource specified in
              the source list

       o      /var/state/apt/lists/partial/  storage   area   for
              state information in transit

SEE ALSO
       apt-cache(8),    dpkg(8),   dselect(8),   sources.list(5),
       apt.conf(5), The APT Users Guide in /usr/doc/apt/

[...]

---------

> Ora quello che non capisco è se siano del tutto equivalenti, quasi- 
> equivalenti o se la prima sia più completa ma più "lenta" o che  
> altro....

Penso che la man page sia abbastanza esplicativa .... :-)

Pero', se vuoi approfondire ogni aspetto di apt-get, ti conviene usare
apt-get HOWTO, che trovi sul sito della Debian o in un suo mirror sotto
documentazione, c'e' anche la versione in italiano. 

Comunque se il tempo non ti manca ... :-) allora puoi estendere i tuoi
orizzonti dell'"universo" Debian scaricandoti anche La Guida di
Riferimento Debian e le FAQ Debian, sempre sotto documentazione ... :-)

Buona lettura .... :-)

Au Revoire
Hugh Hartmann