List available updates but do not install them

Question

I want my cron-run reporting script to notify me in case there are updates for my packages. Is the a way to make apt-get give me the list of available updates but don't do anything more?

Answer 1

apt

For modern versions of apt there is a specific switch for this:

apt list --upgradable

apt-get

For the old apt-get command the -u switch shows a list of packages that are available for upgrade:

# apt-get -u upgrade --assume-no

From the apt-get man page:

-u
--show-upgraded  Show upgraded packages; Print out a list of all packages that are to be upgraded. Configuration Item: APT::Get::Show-Upgraded.
--assume-no  Automatic "no" to all prompts. <== To prevent it from starting to install

Answer 2

apt-get --just-print upgrade

Is not read that easily, below is a perl one liner to parse apt-get's output:

apt-get --just-print upgrade 2>&1 | perl -ne 'if (/Inst\s([\w,\-,\d,\.,~,:,\+]+)\s\[([\w,\-,\d,\.,~,:,\+]+)\]\s\(([\w,\-,\d,\.,~,:,\+]+)\)? /i) {print "PROGRAM: $1 INSTALLED: $2 AVAILABLE: $3\n"}'

This should output something like:

PROGRAM: grub-pc INSTALLED: 1.99-21ubuntu3.1 AVAILABLE: 1.99-21ubuntu3.9

Hopefully it will help someone else,

Answer 3

Another option, inspired by enzotib :

aptitude search '~U' | wc -l

This command will use aptitude to output the new packages and then wc to just count the lines.

On a sidenote, I found that enzotib's solution without the single quotes around the ~U didn't work for me. (Wheezy, ZSH, aptitude 0.6.8.2)

Update :

With the new apt you can do:

apt list --upgradeable

Answer 4

The easiest is:

apt list --upgradeable

Answer 5

You can run

aptitude -F%p --disable-columns search ~U

or the undocumented

/usr/lib/update-notifier/apt-check -p; echo

Another method using an apt-get simulation:

apt-get -s dist-upgrade | awk '/^Inst/ { print $2 }'

Answer 6

apt-get update && apt-get -s upgrade

will list available updates without actually installing.

First command updates package index files before simulated (thus -s) upgrade is done. "-s" will do a simulated upgrade showing packets that would be installed but will not actually install anything.

On the contrary "-u" instead of "-s" would actually install after confirmation.

Answer 7

Take a look at package "apticron":

apticron - Simple tool to mail about pending package updates

Apticron is a simple script which sends daily emails about pending package updates such as security updates, properly handling packages on hold both by dselect and aptitude.

https://packages.debian.org/buster/apticron

Answer 8

I needed full version information on possible upgrades, so I used a modification of jasonwryan's answer:

apt-get -V -u upgrade

It's simple and IMO reasonably formatted output.

Answer 9

apt-get update > /dev/null && apt-get --just-print upgrade | grep "Inst "

is the most simple for cron emails; there is no user iteration, and if there are no updates there is no output.

Answer 10

Just filter the output of

apt-get update && apt-get -s -V -u upgrade

to have only the preferred information in your log.

Most likely, you'll need the beautiful part after the line

...

The following packages will be upgraded:

...

that has few spaces in the beginning.

Answer 11

Jet another on-liner, inspired by this answer:

function a { read input;dpkg -l ${input} | grep " ${input} " | awk '{$1=$2=$3=$4="";print $0}' | sed 's/^ *//';unset input;};{ apt-get --just-print upgrade 2>&1 | perl -ne 'if (/Inst\s([\w,\-,\d,\.,~,:,\+]+)\s\[([\w,\-,\d,\.,~,:,\+]+)\]\s\(([\w,\-,\d,\.,~,:,\+]+)\)? /i) {print "$1 (\e[1;34m$2\e[0m -> \e[1;32m$3\e[0m)\n"}';} | while read -r line; do echo -en "$line $(echo $line | awk '{print $1}' | a )\n"; done;

The output looks like this (colored):

locales (2.13-38+deb7u7 -> 2.13-38+deb7u8) Embedded GNU C Library: National Language (locale) data [support]
linux-headers-3.2.0-4-amd64 (3.2.65-1+deb7u1 -> 3.2.65-1+deb7u2) Header files for Linux 3.2.0-4-amd64
linux-headers-3.2.0-4-common (3.2.65-1+deb7u1 -> 3.2.65-1+deb7u2) Common header files for Linux 3.2.0-4
sudo (1.8.5p2-1+nmu1 -> 1.8.5p2-1+nmu2) Provide limited super user privileges to specific users

If you dont want the short description use this one:

{ apt-get --just-print upgrade 2>&1 | perl -ne 'if (/Inst\s([\w,\-,\d,\.,~,:,\+]+)\s\[([\w,\-,\d,\.,~,:,\+]+)\]\s\(([\w,\-,\d,\.,~,:,\+]+)\)? /i) {print "$1 (\e[1;34m$2\e[0m -> \e[1;32m$3\e[0m)\n"}';} | while read -r line; do echo -en "$line\n"; done;

Output:

locales (2.13-38+deb7u7 -> 2.13-38+deb7u8)
linux-headers-3.2.0-4-amd64 (3.2.65-1+deb7u1 -> 3.2.65-1+deb7u2)
linux-headers-3.2.0-4-common (3.2.65-1+deb7u1 -> 3.2.65-1+deb7u2)
sudo (1.8.5p2-1+nmu1 -> 1.8.5p2-1+nmu2)

Answer 12

apt-check is probably the most efficient scripting method.

/usr/lib/update-notifier/apt-check 2>&1 | cut -d ';' -f 1

A very small modification shows you only the security updates.

/usr/lib/update-notifier/apt-check 2>&1 | cut -d ';' -f 2

Answer 13

I like to use this:

apt-get -qq update && apt-get -qq -s upgrade

You get an output like this one:

Inst linux-base [3.5] (4.5~deb8u1 Debian-Security:8/oldstable [all])
Conf linux-base (4.5~deb8u1 Debian-Security:8/oldstable [all])

if there are available updates, and none if there isn't. This way you can simply couple it with a monitoring solution.

Answer 14

After writing warning to @jasonwryan's answer, I want to provide my own solution:

apt-get dist-upgrade --assume-no

Unfortunately, this one doesn't work with debian wheezy and I had to check some lxc containers which are still not upgraded. This form will always work:

apt-get dist-upgrade </dev/null

Finally, I also wanted to reformat the output. I chose to change the call again (using --dry-run but ignoring all additional output) because it feels more safe:

apt-get --dry-run dist-upgrade | awk '
BEGIN{p=0}
/^The/{p=1;t=$0}
/no longer required/{p=0}
#optional: /been kept back/{p=0}
p && t{print t;t=""}
/^  / && p{print $0}
'

Returns:

The following packages have been kept back:
  iproute
The following packages will be upgraded:
  unzip

Answer 15

There's the apt-show-versions tool. To show available updates run:

apt-show-versions -u

Answer 16

As a variation I use the following:

apt-get -V -s dist-upgrade \
    |grep -E "^   .*=>.*" \
    |awk 'BEGIN {
        ul=sprintf("%*s",40,""); gsub(/ /,"-",ul);
        printf "%-30s %-30s %-30s\n", "Package", "Installed", "Available";
        printf "%-30.30s %-30.30s %-30.30s\n", ul, ul, ul;
     }
     {
        printf "%-30s %-30s %-30s\n",
               $1,
               substr($2,2),
               substr($4,1,length($4)-1)
     }'

Stick it into a script named apt-updates and you can then call apt-updates to get a listing of all updates regardless of user.

You still do need to call apt-get update with privileged access.