PNG(s) to PDF, the command line way

A quick tip for command line users: if you want to convert .png files to .pdf:

convert *.png filename.pdf

Simple! If you want to keep control of page sequence or specific files to convert:

convert page1.png page2.png page3.png filename.pdf

Needless to say, but I’ll say it anyways, the .pdf won’t be in vector graphics, so not scalable but that is because .png is not a vector graphics format.

Diff with vimdiff

For those who are vim fans, a quick tip on how to run a diff/merge  task:

Open the files with:

vimdiff file1 file2 file3   –> Vertical split is default

vimdiff -o file1 file2 file3  –> If you’d like horizontal split of files

To jump between files:

Ctrl-W w

To jump places where differences are found:

]c    –> to see next part of a change

[c   –> to go back to the start of a previous part of a change

These are just the quick basics, there are a ton of other commands listed on Vim’s documentation page.

Encrypt files with GnuPG

Here is a simple and quick way for you to encrypt files in Linux:

gpg –output doc.gpg –encrypt –recipient original_file.doc

Further explained:

  • –output (or -o) is the name of the encrypted file
  • –recipient (or -r) is the person who will be decrypting the file. If the file is for yourself only, use the email address of your GPG key.

To decrypt:

gpg --output output_file.doc --decrypt doc.gpg

I recently used this to encrypt a sensitive file before placing it on my Dropbox account. Nice safe way to place a private document in the cloud.

Reference, GnuPG manual.

Tip: discover and terminate high CPU processes (Linux)

A quick tip to get the dust out of our blog 🙂

If you hear the fan of your computer going way up, most likely that was because some application or process is using too much CPU. Find out which one and terminate it by:
1. Open the terminal
2. Run “top”
3. Press “k” and the number on “pid” column of the process which appears on the top of the list.

Using Twitter with Pidgin

The eco-system around Pidgin is fantastic, below is yet another cool plug-in tip for it.

Pidgin-Twitter plug-in works with Linux and Windows for you to get back into posting to and receiving notes from Twitter (also works well with too!). Steps to get it working:

  1. download and install the plug-in the plug-in;
  2. go to Pidgin menu under Tools > Plug-ins you’ll find Pidgin-Twitter to activate and configure;
  3. place your username / password and define a couple of other options (such as show users’ avatars)
  4. Add a buddy to your GTalk account called and choose to display it even when it is offline.

You’re good to go! Open the chat window for the buddy you just created and instantly it’ll display your messages.

Open source at work

Migrating from a proprietary licensed mindset into open source can be perceived as a pretty challenging task. It is incredibly common for me to see that branding power often blinds people in a way that the functionalities of a software are disregarded in favor of the comforting sound of a brand name.

What does all that marketing blah blah means?

At my work, all new computers have open source software on it. The email client, office suite, browser, image editor, project management software and programming tools are all installed in the new employee’s computer from his/her day one.

But, the adaptation isn’t immediate. The icon, the menu bar, the layout are all excuses for a fuss: “I can’t do this, I can’t do that, where is the icon for this!?” After some guidance and explanation of functions, everything is settled and peace restored.

In your company, if you’d like to start introducing open source programs to support the cause, to reduce costs, or even to have the possibility to tailor some programs to your specific needs, don’t worry it can be much easier than you’d think.

Open source is fit for whom?

For the generalist worker, open source programs will go above and beyond the level of functionality compared to proprietary solutions. It is realistic to say though that some employees will need complex tools to work at full speed. For these team members, proprietary software can be rightfully requested.

How would your company make the transition?

If you’re a part of a large company, make changes with one or two programs at a time. All new employees though make sure they start with the most number of open source tools as you’d like. During the migration process, hold workshops to guide the team and be available to assist at other times when needed.

Overall, be supportive of your team and don’t hesitate to make the move. In the end, open source at work is an easier work than you might have thought!

Free movie tip – D.O.A.

D.O.A. (1950) movie

D.O.A. (1950) movie

Found in the Internet Archive, D.O.A. of 1950 is a classic film noir movie.

Although I’m not a fan of old movies, this drama mystery was pretty worth it. The basic story is of a person who tries to investigate who murdered him. The story is pretty rich with very good moments of suspense and a nice character build-up. The victim who has received a deadly poison goes out to search for his own killer. During this process there are shootings, lots of detective-style work, romantic scenes and brave escapes.

This movie is now released under public domain for download (you can get it in the open source friendly .ogv format).

Top podcasts & vidcasts

Sharing with you my list of Linux and Open Source podcasts and vidcasts I subscribe to:

  • FLOSS Weekly (podcast) – part of the world, excellent interviews with leaders of different FLOSS projects;
  • Linux Outlaws (podcast) – this show is quite informal but has very nice comments on what’s new on the Linux and FLOSS world;
  • Stack Overflow (podcast) – more geared towards programming and software development;
  • The Linux Journal (vidcast) – short but very nice Linux tips;
  • Category 5 (vidcast) – a lot of good information for those starting in the world of Linux with live Q&A session;
  • The Source (vidcast) – just started following it and so far I’ve seen some very nice interviews with important community members of the open source world.

Any suggestions from our readers?

FLOSS Manuals

If you’re interested in Free Libre Open Source Software and would like some valuable reading material to become an expert, FLOSS Manuals is a great site.

You can find books about Blender, Inkscape, Firefox, OpenOffice, Audacity, WordPress, Linux Command Line, to name a few. Find the manual you want, read it on their site, download, or order a printed copy. Only the printed copy is not free.

Also cool is the ability to remix your book to get only certain chapters that you find interesting.

Go there, get some nice reading material and even help out by being a writer or a proofreader.