Category: Linux


At times, we need to combine multiple pdf file’s into one pdf file. However, instead of running to get a dedicated program to join the multiple pdf’s, here is a simple & fast way to do so.

Convert command can be used to merge multiple pdf’s into one. Convert command is a subset of the ‘ImageMagick’ suite of tools. So you’ll need to install it first from your distribution’s repository. On a Fedora/Red Hat system it can be done by;

#yum install ImageMagick

Once installed, simply open a terminal & navigate to the directory where you have the multiple pdf’s which need to be merged into one pdf. Once there issue;

$convert file1.pdf file2.pdf output.pdf

I created a calendar for the coming year & in all had 12 pdf’s for each month which I wanted to be merged into one. Hence, I issued the following;

$convert Jan.pdf Feb.pdf March.pdf April.pdf May.pdf June.pdf July.pdf August.pdf September.pdf October.pdf November.pdf December.pdf calendar.pdf

Here my output pdf file will be named ‘calendar.pdf’. Once you execute the above command, it will take sometime(depending on how big or small & how many pdf’s are) and once done it will return you to the prompt. Now your merged pdf file will be saved in the same folder by the name you gave in the command above.

That’s it! It’s so easy.

RSync is useful for fast incremental transfer of data. It is very popular across business organizations as it comes with some pretty handy features which sets it apart from the rest. Some of them are;

1) Security – One can transmit the data using the ssh tunneling which provides encryption & safety from eavesdroppers.

2) Speed – Since rsync transmits only the data which has changed over subsequent time, the transmission is fast as only the bits which are changed are transferred & not the entire file. This can mean tremendous saving of time. It also comes with options which lets you fine-tune the transfer which can further improve the transfer speed.

3) Less Bandwidth Intensive – Rsync uses compression & decompression algorithms at the sending & receiving end respectively. This not only speeds up the transfer but also saves the bandwidth.

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Install Cisco Packet Tracer under Linux

Cisco Packet Tracer can be a very useful tool for learning about networking without needing to spend tons of money(infact, none). The simulator allows you to create a networking topology & then carry on your configurations & changes before they can be implemented in the real world networking environment. This is critical as you get to learn from any mistakes in simulation thus not needing your network to act as a guinea pig. Here, I’ll show you how you can install the Cisco Packet Tracer under your linux system. I would be installing it on Fedora 18.

Cisco Packet Tracer Linux

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The ‘Recent’ item under places in nautilus sidebar can be handy for accessing recent files on the system. However it can also be a privacy breach. There seems no easy setting to hide the ‘recent’ entry under places. Hiding the sidebar option will hide it completely. Here is a way to hide the ‘recent’ places under the file manager. Actually this does not hide the recent places, but does not allows any files to be listed there in the first place. After doing the following, you’ll see the ‘recent’ under places but there won’t be files listed in there.

The items shown under the recent are stored in a file which is dynamically modified as the user access the files over the system. Simply delete the file containing the recent items history using the following command.

$rm -rf ~/.local/share/recently-used.xbel

Now you’ll need to logout & relogin for changes to take effect. However this is only a one time solution. You’ll need to manually run this command from time to time to clear the recent items.

If you want to save this hassle, you can do the following changes to clear the recent items from not showing up at all. A permanent fix would be to first delete the above file. Now immediately before you open any of your documents(audio, video, text or any file), open a terminal & do the following.

$cd ~/.local/share/

$touch recently-used.xbel

$su

#chattr +i recently-used.xbel

That’s it & you’re done. Now ‘recent’ items under the sidebar will always be empty. To know more about the chattr command, read this post.

GIMP is a good free software for photo-editing. It has most of the capabilities you will require of its commercial counterpart Adobe Photoshop. What’s more with the right plugins, you can extend its capabilities. Here I’ll tell you about some GIMP plugins which will primarily be of interest to photographers. They will make your photo work-flow easier & faster.

GIMP-logo

Vignette – As the names suggests, this adds a vignette to your photo. Vignette can be used creatively to allow viewer’s eye to stay within the frame. Most of the photos will benefit from a small amount of vignette. The vignette plugin allows you to choose parameters like vignette colour, softness, darkness etc. It does its job very well.

Lomo – Want to mimic the look of a LOMO camera? This plugin will do it for you. It saturates the colour, adds a vignette(there is also an option for double vignette) & some other parameters for fine-tuning the output. Have fun!

Split Tone – Split toning is another beautiful effect. This plugins lets you select the two colours for split toning(as oppose to just two offered by most other programs) & end up with results beyond your imagination. Give this a try.

Darla Contrast Fix – This plugin aims to normalize the contrast in the photograph. With the right settings, it can make a photograph. However, this plugin requires some practice & knowledge of the parameters before one can get consistent results regularly.

National Geographic – Have you always wondered at the quality of the photos published by Nat Geo? They are sharp, contrasty & look as if edited by professionals. This simple plugin will put the same power in your hands too. This is a great plugin & as Darla Contrast Fix, this too requires practice before you’re able to get consistent results on a regular basis.

G’MIC – Stands for GRECY’s Magic for Image Computing. This is a grand-daddy of plugins. It is so packed with various image manipulation tools that I wonder even if someone will discover all of them in lifetime. Right from the basic sharpening, noise reduction to advanced like soft glow. This covers it all. And did I say, each of the tools come with several more options to fine tune the output? Yes, this is one hell of a plugin.

Off-course, there are many more plugins in the GIMP repository but these are the few I use on a regular basis & find to work properly. If you have your favourite GIMP plugin not listed here, do share it below. Will benefit all. :)

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