wodow's questions

foreman can read .env files and set environment variables from the contents, and then run a program

e.g. foreman run -e vars.env myprogram

...but it does a lot of other things (and is primarily concerned with starting things using its Procfile format).

Is there a simpler (Linux/Unix) tool that's just focussed on reading .env files and executing a command with the new environment?

Example environment file (from http://ddollar.github.io/foreman/#ENVIRONMENT ):

FOO=bar
BAZ=qux

I do this too often:

$ pwd
/a/long/long/way/from/anywhere
$ cd # oops - meant to tab-complete something
/home/$USER

Can cd defaulting to $HOME be disabled?

On a single Linux server, there are often lots of independent (perhaps interlinked) services outputting numerous logs to files at known paths.

Sometimes bad stuff happens and is written about, to the logs. Sometimes the services lock up and the logs get no (or perhaps very few) new entries.

What's the simplest way to monitor both of these kinds of events using one tool/service/system?

On Apache2, I have a VirtualHost with a number of <Directory> directives/sections containing multiple access control statements

i.e.

<Directory /foo>
    Order Deny,Allow
    Deny from all
    Allow from ...
    Allow from ...
    ...
</Directory>
...

Is there a way to specify the access control at a higher level (above <Directory>)? Or should I be using macros?

Thanks in advance!

Does there exist a forward proxy server that will lookup and obey robots.txt files on remote internet domains and enforce them on behalf of requesters going via the proxy?

e.g. Imagine a website at www.example.com that has a robots.txt file that restricts certain URLs and applies Crawl-Delays to others.

Multiple automatic clients (e.g. crawlers, scrapers) could then, going via the proxy, access the website at www.example.com without violating the robots.txt directives AND without having to access the file themselves (=> simpler clients and less requests to get robots.txt)

(Specifically, I am looking at the "GYM2008" version of the spec - http://nikitathespider.com/python/rerp/#gym2008 - because it's in wide use)

If I have a piped command such as

   cat myfile | processor_application

where processor_application is something reading from standard in, in chunks, to process, is it possible to see how far through the file cat has got?

Possibly using lsof?

Thanks!

A script regularly initiates an SSH connection from one server to another, using SSH keys.

However, once, the keys were briefly overwritten. This caused the SSH client to fall back to asking for a password, which had undesired knock-on effects.

Is it possible to instruct SSH to exit if key-based auth fails, and not fall back to asking for a password?

Thanks!

Wodow

The standard split command on Unix/Linux allows you to split files into fixed size pieces in terms of bytes or lines, with the output file names suffixed with letters or numbers (e.g. PREFIXaa, PREFIXab, ... or PREFIX1, PREFIX2, ...)

However, it's not clear from the output names alone how many pieces there should be.

Is there a standard tool that will do this, i.e. outputting to e.g. PREFIX1of4, PREFIX2of4... or similar? Or is this a job for Perl (i.e. I find a Perl script).

Thanks!

Wodow

I have a number of Linux servers (dedicated and VPS) with their own fixed IP addresses.

I would like to be able to acquire a set of long-lived IP addresses that could then be assigned to the servers in a manner of my choosing (and to new servers in the future).

My thought is that this would be a service provided by (major) ISPs - IP addresses that they could route as part of their network ops.

Do such services exist? What are they called

(I realise that I could do this with a dedicated server and some proxy setup, but a service would be better)

Thanks for thoughts!

I would like to rewrite the contents/payload of UDP packets as they are received by a machine, on selected reports - before they are passed to the listening application.

For example, I would like to change the headers of a UDP-based protocol by using grep-like regular expressions (to add, remove or change parts of each message received).

Is this possible with a software firewall or similar tool?

Thanks all!

What is the best way to check that all email sent out of a network (e.g. via a single, common SMTP server) meets arbitrary criteria, otherwise redirecting, bouncing or sending warning messages as required?

Example criteria:

• Certain headers are set if others are set.
• If a specific address is used, inject another as a CC

Do most/all MTAs work like this, or is there a better way to go about it, using a tool or service in between?

Thanks!