Mostly Unixish - Alan's amusing and surprising homepage

SCP taming: stop local silliness

Every day now and then, I get an scp command wrong. Scp is designed after commands like rcp and works totally fine for local-to-local file copy. While this can (or could) be useful

Command line data crunching with Python

Every time I'm doing some data crunching on the command line, I find myself juggling between sed, awk, sort, uniq, etc. While I like the UNIX way of having one tool doing one

Git: automatically set and use multiple commit identities

Sure, git is great. Sure it is possible to use multiple commit identities in git - just set local per-repo variables. If it weren't for the fact that chances of forgetting about it

badblocks: test your mass storage!

Are you unsure whether your mass storage works properly? Do you suspect it's faulty somewhere? Verify it with a nifty tool, included in most Linux distros and in macOS if you install the

Automated cleanup of Docker leavings

As much as I like Docker, one thing it doesn't do well: cleanup whatever is left on my hard drive after running it for a while. There're generally two kinds of Docker Waste:

Python requests SSL and InsecurePlatformWarning

Every now and then, when using Python 2.7 < 2.7.9 and trying to access SSL resources, especially through the requests toolkit, which seems to trigger the issue frequently - but

chmod and the capital X

This is one very, very, very interesting piece of ancient wisdom. Suppose you need to change permissions for some directories. Maybe the permissions are too strict, e.g. something like 700 for directories

Kill Me Softly: killing a process The Right Way

I was tired of repeating the same old pattern. Send a kill signal. Check with pgrep. Did the process exit? Send a kill -9. Now all my knowledge has been permanently dumped here:

Unfreezing your desktop: when Compiz goes wrong

A desktop freeze is something that's not so rare nowadays - that's not good, but we shouldn't get desperate about that. I like Compiz with Unity Desktop on my Ubuntu Trusty very much;

Don't give a shell to system users - use su

I seem very ancientwisdom-oriented these days. Sometimes you've got a system user on your linux server that's used to run a specific service; it's a good practice to employ those users to achieve

SSH hostnames configuration and shortcuts

This is another old trick, but I like to tell the world about such amenities. I often find people writing command lines such as: ssh arcane-system-user@someextremelylong.andimpossibiletotype.anderrorprone.hostname.com or, worse

I wish sudo would ask for my password less often

This is a very old trick, but I find many people doesn't know about it yet. If you're using sudo (and you definitely should), one minor complaint is that you need to re-enter

Ubuntu: faster release upgrade

It might be high time to update to the latest Ubuntu 14.04. I think that the upgrade process that is provided by Canonical is slightly underoptimal: if you're using a local mirror

Keep your tomcat instance up-to-date, and keep apps and configuration tidy.

UPDATED: 26th January 2015, with Tomcat 8 support. Today I'm gonna share something that I figured out some times ago: how do I keep my tomcat installation up to date on my servers?

Puppet Http Source for files

Sometimes you would like to use an http URL as the source file for puppet; while it's being discussed since long, no implementation has been created so far. Of course it would be

Quick log for bash scripts, with line limit

Sometimes you need to write a quick shell script; many a time, you need to put it on a server, and launch it every now and then, or run it in a cron

apt-get update: fixing 'package index files are corrupted'

Sometimes when performing your daily apt-get update, you'll experience messages like E: The package lists or status file could not be parsed or opened. or The package index files are corrupted Such messages

Wmctrl: gather and focus your chosen window by hotkey

I find it extremely handy to be able to recall my windows by just using the keyboard. It's pretty easy to do in Linux, just use: wmctrl -x -R <WM_CLASS>

ssh-copy-id with nonstandard sshd port

UPDATE: modern ssh-copy-id often support a -p parameter for the port. So this trick is unnecessary and won't probably work. ssh-copy-id is a cool script which is usually distributed along openssh client nowadays;

ssh client: stopping key verification complaints inside your own private network

If you develop enough software, most probably you'll have a test/development network at your service. In such networks, which are usually handled through a virtualization infrastructure, machines come and go very quickly.

Thunderbird temporary directory

Whenever you use Thunderbird on Linux you may encounter one annoying behaviour. If you open a message which is got an attachment - you just need to open the message, not to save

Disown is your friend

Bash builtin disown is a not-so-well known [job control command] http://www.gnu.org/software/bash/manual/html_node/Job-Control-Builtins.html), and yet it's an extremely useful one. So what? You've started a

Purging outdated kernels on systems with unattended-upgrades

Whenever I install a production system/server I tend to enable full automatic updating, because it's usually better that something breaks because of a failed update rather than leaving a production machine unpatched;

Dropbox and Mercurial: and lived happily ever after

Some days ago I ranted about an issue I had with Mercurial and Dropbox; basically, I did put a mercurial repo in a dropbox folder, and ended up with this kind of mess