Tag: ubuntu

Troubleshooting the installation of IRAF on Ubuntu

So, found myself installing IRAF on a friend’s laptop running Ubuntu. There are some decent tutorials online about the general steps: for example, this one, and the official one. However, they all skip all possible issues that could come up (or at least, that popped up in my case). This is another good resource about the setup, config and usage (but skip the Ureka parts).

The community-maintained version of IRAF allows easy installation on some systems, such as Ubuntu.

The thing is that IRAF is a jumble of stunningly old pieces of software working together on primitive terminals and on peculiar conditions.

In random order, possible issues/tips are:

  • If the packages iraf-all pyraf-all stsci show as non-existent, you have not added the astroconda channel. The command should be
    `conda config –add channels http://ssb.stsci.edu/astroconda`
  • You will still need to manually install ds9:
    `sudo apt install saods9`
  • You do not need to change the default shell to tcsh, although you need it to be installed:
    `sudo apt install tcsh`
  • If xgterm does not execute with error File not found, although the file is clearly there, make sure you have installed 32 bit dependencies:
    `sudo apt-get install libc6:i386 libz1:i386 libncurses5:i386 libbz2-1.0:i386 libuuid1:i386 libxcb1:i386 libxmu6:i386`
  • If `conda` commands do not work, make sure you have activated the Python environment containing the iraf packages:
    `cd /path/to/iraf
    source activate iraf27`

In the end, the exact set of commands that got the whole environment working has been: Continue reading “Troubleshooting the installation of IRAF on Ubuntu”

Base conversion in Ubuntu (decimal to binary)

Need to convert a base 10 integer in a base 2 one? Or, at any rate, convert a number from one numeration system to another? In Ubuntu, the bc utility already integrates these features. It is usually already installed, so you don’t have to anything special.

Simply run bc, and enter the following commands:

ibase=10
obase=2

Then, all subsequent number inputs will be simply converted to their base-2 representation.

If you want to get a conversion straight ahead, without going through the opening of bc, just enter the following from a terminal:

echo 'obase=2; ibase=10; 123' | bc

which will convert the number 123 from base 10 to base 2.

Of course, 2 and 10 can be replaced with any other possible base!