No more space left on /tmp under Fedora

Under Fedora, one of my software requires more than 4Gb of temporary space and I realised that the /tmp directory is limited to 4Gb. In order to increase the /tmp directory, just edit the /etc/fstab file and add this line (to extend to 8Gb instead of 4Gb):

Then, as root:

That’s it. You can check that you have now 8Gb available in /tmp by typing

Posted in Linux | Leave a comment

blasr (pacbio) installation on fedora box

I wanted to use blasr tool for Pacbio mapping and had difficulties in using or installing the tool. I first use a local installation of the tool on the provided cluster and it look like the installation was quite old. I then use a bioconda version. The latest version (5.3) was not working on my system (missing library) and this was reported. The previous version worked (5.2) but was missing a needed configuration flag. So, I decided to follow the instructions from pacbio to install a local version. That was not straightforward but finally got it to work. My platform is Fedora 23 and the instructions were given for ubuntu or centos 6.

First, download the source code:

This command installs zlib, bzip2, boost and hdf5 to start with.
The first issue arised from an error in the compilation of the hdf5 dependency due to missing iostream in the compilation of the hdf5 library

The solution was to edit the Makefile in workspace/hdf5-1.8.16/c++
and to comment this line (adding a # character in front))

Come back to the main pitchfork directory, type the make command again (see above). Another failure due to similar compilation error related to the namespace occured. Again, I edited the Makefile in
workspace/hdf5-1.8.16/c++/test/Makefile and commented the same line.

Next, I got a linking issue

This was solved by installing the stdc++ static library. I figure out the solution by typing:

to see that none of the standard path could find the library despite the presence of the /usr/lib/

Again, type

I got

so again, needed to find the culprit: a Makefile and it was in
In workspace/hdf5-1.8.16/c++/hl/test/Makefile . Again comment the same line as shown above.

Back to blasr, the make then failed when trying to install ncurses.

Here I tried a different strategy and tried to use the packages installed with my conda environement. To do so, I edited the and added:

Then, same issue with samtools, so added

Then, there was an error in the ./bin/pitchfork module due to a Python 3 issue (I had already switch all print “” to print(“”). Here, the issue was

Just replace _out[0] with str(_out[0])

Then, blasr compiles successfully…time to run it; The executable seems to be in workspace/blasr/blasr:

./workspace/blasr/blasr: error while loading shared libraries: cannot open shared object file: No such file or directory

Here, you need to add a bunch of path to your LD_LIBRARY_PATH:

Posted in biology | Tagged , | Leave a comment

swapping two columns with awk keeping tabulation

Assuming you have a data file with N columns and you want to swap the first and second one, just type:

To keep the tabulation intact, you need to specify the separator.

Incoming separator is defined by -F $’\t’ and the separator for the output is defined by OFS=$’\t’.

Posted in Linux | Tagged | Leave a comment

set a default version to an environment module

Context: “The environment modules package provides for an easy dynamic modification of a user’s environment via modulefiles. which typically instruct the module command to alter or set shell environment variables such as PATH, MANPATH, etc. as well as define aliases over a variety of shells.”

Reference: modules.sourceforge

When you type “module av PKGNAME” you get a list of available version for the PKGNAME. You may see the (default) one.

By default, the highest lexicographically sorted modulefile under the directory is set as the default. However, you can change this behaviour by creating a .version file in that directory which has a format like the following

Posted in Linux | Tagged | Leave a comment

fedora aeroplane mode always on

Under Fedora 23, somehow the aeroplane mode went on (plane icon shown in top right corner). I tried to switch it off but could not. After a reboot, the aeroplane is still switch on and there is no way to switch it off. So, neither wire connection nor wifi connection can be switch on.

After a while and some browsing, this solution worked for me:

Note, however, that on my system rfkill was not installed… so i got the RPM (rfkill-0.5.6.fc23.x86_64.rpm) from another source, copied it on a usb key and install it as follows:

Posted in Linux | Tagged | Leave a comment

packet_write_wait: Connection to XXX : Broken pipe

In general, I can connect to a remote machine via SSH without any troubles but occasionally in some particular setup, although I can connect to the remote machine and type commands in a shell, the connection is broken after a few minutes of connection.

This happens when we do not interact with the terminal (i.e., we do not type anything on the keyboard).

In such case, the following error message appears:


On the host, add those lines in the file .ssh/config

If the file config does not exist, just create it.

The ServerAliveInternal pings the server with a null packet every 30 seconds. As for the second line, I have not check whether it is required or not.

Posted in Linux | Tagged | Leave a comment

pytest-cov collects no data on Travis

I recently switched from nosetests to pytest and pytest-cov for one of my Python project (

Locally, everything seemed to work fine and once on Travis, all tests passed as expected.

Yet, before the coverage report, I noticed this warning:

and more importantly, the final coverage reported was 0% !!

I later realised that one file in the test/ directory was present locally but not in the github source code. After a commit, travis found the missing file and the coverage came back to normal.

So, this seems important for pytest-cov

Posted in Python | Tagged , , | 4 Comments

Remove extension in a bash script

Imagine a bunch of files with extension fastq.dsrc, the following script will decompress the files by looping over the N files. One issue was to remove the extension in the script. See below the usage of //

Posted in Linux | Tagged | Leave a comment

git synchronisation of a forked repository

Let us assume you have forked a repository (from You now have a local version at a given time of the repository repository_name.

Time flyes and you come back to the local repository and you are not synchronised anymore. So, you need to fetch the new commits from the upstream repo, pull and push into your repository. this is done as follows:

Posted in Uncategorized | Leave a comment

gimp: how to make a transparent background

How to make a transparent background/selection on an image using GIMP

    1. Open your image.
    2. Select the area you want to make transparent.

    1. Select the appropriate selection tool from the Tool window or the Tools – Selection Tools menu on the Layer window. I usually use the magic wand/fuzzy select (Select contiguous region) tool or the Select regions by color tool.
    2. Click in the region you want selected. Use shift-click to add more regions/colors.Tip: It’s easier if you zoom in (View – Zoom menu) to see finer details of exactly what you’re selecting.

    3. In the Layer window (the one showing your image), select Layer – Transparency – Add Alpha Channel.If this is blanked out then it’s already done. This makes sure your image can store transparency data
    4. Select Edit – Clear. This makes the selection transparent.
    5. Save the file. Note: If you save it as a PNG file, be sure to select the ‘Save colour values from transparent pixels’ option in the Save as PNG dialog box.

Posted in photos | Tagged | Leave a comment