Upgrade a single package with apt-get?

Question

simple question, hopefully simple answer;

how do i update a single package? as far as man apt-get says,

 apt-get upgrade

doesn't take a package/list of packages as parameter:

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 circumstances 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 versions of packages are available.

Answer 1

You just need to do apt-get install <packagename>. This will upgrade only that single package.

Answer 2

sudo apt-get --only-upgrade install packagename

eg. sudo apt-get --only-upgrade install ack

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Skipping **ack**, it is not installed and only upgrades are requested.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Answer 3

There are two possible ways I can think of:

1. sudo apt-get install nameofpackage

   This will upgrade the package even if is already installed:

   ~$ sudo apt-get install emesene
   Reading package lists... Done
   Building dependency tree       
   Reading state information... Done
   The following packages will be upgraded:
     emesene
   1 upgraded, 0 newly installed, 0 to remove and 5 not upgraded.
   Need to get 1,486 kB of archives.
   After this operation, 696 kB disk space will be freed.
   Get:1 http://il.archive.ubuntu.com/ubuntu/ natty-updates/universe emesene all 2.11.4+dfsg-0ubuntu1 [1,486 kB]
   

2. UsingSynaptic Package Manager: Right click→Mark for upgrade:

   

   Note: Sometimes it may asks for additional packages or dependencies, it is normal.

Answer 4

For a command line solution that doesn't install the package if it doesn't already exist:

dpkg -s <package> 2>/dev/null | grep -q Status.*installed && sudo apt-get install <package>

This can easily be made into a script, e.g.:

upgrade-package.sh:

#!/bin/bash

[[ -z $1 ]] && { echo "Usage: $(basename $0) package"; exit 1; }

if dpkg -s "$1" 2>/dev/null | grep -q Status.*installed; then
    echo "Attempting to upgrade $1"
    sudo apt-get install "$1"
else
    echo "Package $1 is not installed"
fi