How to move all CPAN installations from one perl version to another?

cpan as a built-in option for this purpose. First, create a bundle of all existing packages. For this, load the older perl version which will be the source for all cpan modules:

module load perl/5.22.1
perl -MCPAN -eautobundle

This will print all the CPAN modules that it puts in the bundle. Once complete, you’ll see:

Wrote bundle file

Now, unload the older perl and load newer perl:

module purge
module load perl/5.24.0

And install modules:

perl -MCPAN -e 'install Bundle::Snapshot_2017_05_09_00'

It should install all CPAN modules in the bundle!

How to prevent SSH from disconnecting if it’s been idle for a while

If you’re using HPC, chances are that your University/Sysadmin has a policy about how long you can stay inactive with the established SSH connection. If you are frustrated with this automatic disconnections, here is a way to prevent this. You can either:

ssh -o "ServerAliveInterval 60" -X

or create a file in ~/.ssh/config with the following line:

ServerAliveInterval 60

This will enable ssh client keepalives. The above line will send an ssh keepalive every 60 seconds that will prevent network devices from considering the session as idle.


How to insert word like comments in Overleaf/Latex documents?

There is a todo package that can be used for this purpose. Simply add these lines to your document and you can leave comments with \todo commands.


The above package will be used in most documents, so no need to add it if its already there


by default it will be on right, to put it on left (if you don’t have room beacuse of margins) use


For commenting

\todo{this is an example comment}

Comments will be show as follows:

2017-08-17 21_17_08-Overleaf.png