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Installing IRAF/PyRAF from the (Debian) repository directly

IRAF has become lately available through Debian‘s repositories. So I was curious to see how it works. But I was missing the right moment. About a month ago, I finally found the proper motivation so I went on to install it. As always … there were a few, minor, problems. Thanks to John K. we […]

Fixing GPG error “NO_PUBKEY”

In Debian, Ubuntu and similar distros that use the APT (Advanced Package Tool – which is a set of tools for managing Debian packages / applications), to update the system you need to run: sudo apt update This will read all repositories (as they are listed in /etc/apt/sources.list and under /etc/apt/sources.list.d/) and checks if everything […]

Installing Debian on Lenovo Thinkpad Carbon X-1 (Gen 6)

It is exciting to have a new machine, such the Lenovo Thinkpad X-1, but the process for setting it up can be a bit tedious. So this is a small guide what worked or didn’t through my small experience in installing Debian linux. [Just for the fun of it I proceeded with the installation of […]

Merging catalogs and creating unique identifier in bash

For a certain project I had created a number of photometric catalogs, each one corresponding to a specific observing field. I would like to construct the final (merged) one but for this I needed to add a unique source identifier at the beginning of each row. I decided to create a F#-**** tag for each […]

Shared folder in linux

Suppose that we want to create a folder in which multiple users will have full access (which means that they will be able to read, write, and execute). We create the folder (under ‘/’ in this example, although it can be anywhere else): sudo mkdir test which has the following permissions: drwxr-xr-x 2 root root […]

Installing matplotlib through pip but no plot displayed

The easiest way to install any Python package is through PyPI. So, matplotlib is not an exception and we installed it on a CentOS (v6.4) machine without any errors (of course after updating numpy). But when we tried to plot something we couldn’t see anything. This is actually a backend issue, and when we installed […]

Updating clock time through terminal

In my Fedora 14 desktop I keep losing minutes without knowing how and why (doesn’t the clock update automatically?). At the beginning I tried to change the file /etc/ntp.conf (edit it and change the parameter server to: ‘server pool.ntp.org’; 1) as perhaps the server did not respond correctly. I tried to update by: ntpdate pool.ntp.org […]

Fast notes on screen

> list sessions: screen -ls > resume session: screen -r > reattach (if necessary detach first): screen -d -r > detach session: screen -d > detach session (while running – keyboard shortcut): “ctrl+a”+”d” > kill session (inside session): “Ctrl+a”+”:quit” or the more obvious … “exit” > kill session (outside, list sessions first): screen -S session_number […]

Linux backup and restore filesystem –notes

A quick note on how to backup and restore (if necessary) the filesystem. We go to the root directory (/) and as root we run: tar cvpzf backup.tgz –exclude=/lost+found –exclude=/backup.tgz / c: create new archive v: verbose p: preserve permissions z: gzip f: use file (name of file=backup.tgz) We exclude all the directories that we […]

Zip multiple directories separately

In order to zip simultaneously a number of directories, but keep them separate, the following command will just do the job (in bash): for i in *; do zip -r $i.zip $i; done (caution: all directories inside which this command is executed will be zipped, so make a separate directory only to create the zip […]