How to run a command before download with apt-get?

Question

How can I run a command before apt-get starts to download a package?

I know about the dpkg pre-invoke hook ( hook a script to apt-get ), but that seems to be run after the download.

$ apt-get update
Get: 11 http://security.debian.org/ wheezy/updates/main qemu amd64 1.1.2+dfsg-6a+deb7u7 [115 kB]
Fetched 70.9 MB in 10s (6,776 kB/s)
refreshing freenet index
--2015-05-19 15:55:25--  http://127.0.0.1:8888/freenet:USK@oRy7ltZLJM-w-kcOBdiZS1pAA8P-BxZ3BPiiqkmfk0E,6a1KFG6S-Bwp6E-MplW52iH~Y3La6GigQVQDeMjI6rg,AQACAAE/deb.mempo.org/-42/

What we need is to run a command before the download. More exactly: The script must run after calling apt-get but before apt-get accesses any online resource.

Is there something like a Pre-Download hook?

It is important that the installation can be done without having to replace the script apt-get (and without doing anything else which could be undone by an update).

Answer 1

What about using apt pre/post-invoke hooks?

Essentially it is similar to dpkg pre/post-invoke hooks but for apt (which I'm assuming is actually the important one in your usage scenario). AFAIK there are others but I've only used like this.

E.g.

$ sudo cat /etc/apt/apt.conf.d/05new-hook
APT::Update::Pre-Invoke {"your-command-here"};

Answer 2

First determine where is apt-get using whereis apt-get or which apt-get; I will assume it's in /usr/bin/apt-get

Then create a file in /usr/local/bin/apt-get with this content:

#!/bin/bash
# (commands to run before apt-get)
exec /usr/bin/apt-get "$@"

now chmod +x /usr/local/bin/apt-get.

This should survive all upgrades of the distribution but it should not change the behavior of apt-get (aside from running the command before doing anything else). As bonus, it could parse the command line arguments to only run the command when it is truly needed.

(This answer builds upon the answer from Mohammad Etemaddar, merged with the feedback from muru)

Answer 3

You can use an "alias" in the .bashrc file. For example, put that in your root .bashrc file:

alias apt-get='echo blahblah && apt-get'

Command-line arguments will be added automatically to the end of the alias.

Just replace echo blahblah by the command you need.

But in this case, it only works when you're executing commands as root (not sudo).

Answer 4

First determine where is apt-get using whereis apt-get; I will assume it's in /usr/bin/apt-get

as muru says, You can create a script named apt-get in /usr/local/bin/ which is before /usr/bin in Debian and Ubuntu $PATH. Then put the following code to it (/usr/local/bin/apt-get):

#!/bin/bash
commands to run before apt-get
/usr/bin/apt-get "$@"

Thanks muru for offer as comment.

Other way:

Of course there's another way which is not better than previous one.

You can mv /usr/bin/apt-get /usr/bin/apt-get2

Then create a file in /usr/bin/apt-get with this content:

#!/bin/bash
commands to run before apt-get
apt-get2 "$@"

now chmod +x /usr/bin/apt-get

Answer 5

Try an alias in the .bashrc file. It only works when logged in to the account that the file corresponds to. The syntax of an alias is:

alias newcommand='command1; command2; command3' So your line might look a bit like this:

alias apt-get='firstcommand; apt-get'

Or this:

alias apt-get='firstcommand && apt-get'

With the second, apt-get will only execute if firstcommand succeeds.