Formatting XML using Python or PHP
To format XML files usually I use option 3 described in How to pretty print XML on GNU/Linux but recently I've needed to work with XML files which in addition to being obfuscated one part of it use html entities.
How to pretty print XML on GNU/Linux
The obfuscated XML files are difficult to read because the content of the file occupies a single line. Today LibreByte offers 3 tools that allow you to format an XML file.
Tool 1: web browser, examples: Mozilla firefox, Google Chrome. The disadvantage of using a browser is that you can not edit the XML file, only useful if you if you want to view it and nothing more.
Tool 2: use xml_pp, xml_pp is part of the XML-Twig suite, to install it on Debian GNU/Linux type:
$ sudo apt-get install xml-twig-tools
You can then format the XML file by typing:
$ xml_pp -i mifichero.xml
If you want to save the formatted content in another file, type:
$ xml_pp mifichero.xml > mifichero_pp.xml
If you want to edit the formatted file, you can use any text editor.
Tool 3: Use Geany editor and prettyprinter plugin, to install it on Debian GNU/Linux type:
$ sudo apt-get install geany geany-plugin-prettyprinter
After running the above command, you must perform the following steps to activate the plugin
1. Run Geany
XFCE:
Menu-> Development-> Geany
From the console, you can also type:
$ geany &
2. Find the Menu
Tools -> Plugin Manager
3. Activate the plugin XML PrettyPrinter
Once the plugin is activated, the option to format XML appears in the Menu:
Tools-> PrettyPtrinter XML
Further reading
– man xml_pp
– Geany Project
– XML-Twig
– Geany un IDE ligero
Anonymous functions in PHP
With the release of version 5.3.0, PHP development team incorporated what are called anonymous functions or closure.
An anonymous function, as its name implies, is nothing more than a function that has no name and that can be used as a callback allowing greater elegance and readability of source code, it is also possible to assign an anonymous function to a variable as were another data PHP type. PHP internally converts this variable in an instance of the Closure class.
Convert video file to watch on a DVD player
Some DVD player do not support video in high definition resolution then it is necessary to convert it to a supported format, so
* Look for your DVD player specifications
* Look at the details of the video file that you want to convert using MediaInfo
* Use a video conversion tool, in this case we will use avconv which is part of the Libav suite
The following example assumes that your DVD supports:
* Video mpeg4 simple profile format,
* mp3 audio format
* 720 frame size (width) by 576 (high).
Install Libav and libmp3lame on Debian GNU/Linux
$ sudo apt-get install libav-tools libmp3lame0
Perform the conversion
$ avconv -i fichero-origen -f avi -vtag divx -c:v mpeg4 -c:a libmp3lame -s:v 720x576 -aspect 16x9 -qscale 3 fichero-destino
where:
-f, the destination file format, usually avconv guess the format from the extension of the destination file
-vtag, specifies that we will use fourcc divx video codec to mpeg4 (Simple Profile)
-c:v, video code that will be used during the conversion
-c:a, code of audio that we will use during the conversion
-s:v, the frame size
-aspect, aspect and ratio that will have the resulting file. Is recommended to be the same as the original file to achieve good picture quality
-qscale, value between 1-31. A value of 1 means that the resulting file will have the same quality as the original file
Further reading
– man avconv
Failed to decompress file .tar.bz2
If when you try to unpack a file .tar.bz2, you get the following error messages:
tar (child): bzip2: Cannot exec: No such file or directory tar (child): Error is not recoverable: exiting now tar: Child returned status 2
You must solve it by installing the bzip2 package
# apt-get -y install bzip2
Further reading
– man tar
Copy a range of lines from a file to another
To copy a range of lines from a file to another:
1. Open the file in VIM
$ vim fich
2. Execute the following command within the editor (press Esc while in insert mode)
:num-sup-line,num-inf-linew! file-name
Example:
:10,50w! file-name
Further reading
– help write
MediaInfo – detailed information of an audio or video file
MediaInfo is an utility that allows you to:
- Read various audio and video formats
- Show information in several formats: text, html, spreadsheet, hierarchical,…
- Customize the previous views
- Exporting information as text, csv, html…
The following is the information dumped by MediaInfo:
- General: title, author, director, album, size, …
- Video: codec, aspect, frame per second (fps), bitrate, width, height, …
- Audio: codec, channels, language, bitrate, …
- Text: subtitle language
MediaInfo supports following formats:
- Video: mkv, ogm, avi, divx, quicktime, mpeg-1, mpeg-2, mpeg-4, …
- Audio: ogg, mp3, wav, acc, m4a, …
- Subtitles: srt, ssa, ass, sami, …
MediaInfo can be used through its graphical interface, command line interface or integrated into an application using the API.
To install MediaInfo (cli) in Debian GNU/Linux type:
$ sudo apt-get install mediainfo
In order to obtain information from a file type:
$ mediainfo buffers_listed_and_hidden.ogv
General ID : 280403682 (0x10B69EE2) Complete name : buffers_listed_and_hidden.ogv Format : OGG File size : 4.61 MiB Duration : 3mn 28s Overall bit rate mode : Variable Overall bit rate : 186 Kbps Writing application : ffmpeg2theora-0.25 SOURCE_OSHASH : 3fd514e6b64347ca Video ID : 889190165 (0x34FFF715) Format : Theora Duration : 3mn 28s Bit rate : 89.5 Kbps Nominal bit rate : 297 Kbps Width : 640 pixels Height : 480 pixels Display aspect ratio : 4:3 Frame rate : 30.000 fps Compression mode : Lossy Bits/(Pixel*Frame) : 0.010 Stream size : 2.22 MiB (48%) Writing library : Xiph.Org libtheora 1.1 20090822 (Thusnelda) Audio ID : 1236641633 (0x49B5A761) Format : Vorbis Format settings, Floor : 1 Duration : 3mn 28s Bit rate mode : Variable Bit rate : 80.0 Kbps Channel(s) : 2 channels Sampling rate : 44.1 KHz Compression mode : Lossy Stream size : 1.99 MiB (43%) Writing library : libVorbis 20090709 (UTC 2009-07-09)
Further reading
– man mediainfo
– MediaInfo project
VIM a powerful and flexible text editor
The first version was released in November 1991, for the Amiga platform. A year later came the first version for UNIX. Its author, Bram Moolenar, was inspired by VI editor, very popular among the UNIX followers. Vim inherits the features of VI and adds new ones, being a 99% compatible with its predecessor when it starts in compatible mode.
Its development model under a GPL compatible license and the new built-in features made VIM gain a lot of followers very quickly becoming one of the most popular editors. Currently the most GNU/Linux distributions incorporate it as the text editor by default.
Basic modes
- Normal. Using key combinations you can perform actions such as: copy and delete words, groups of words, lines, go to start, at the end of the file, etc. It is the default mode when you start the editor
- Insert. Allows you to edit the file on which we are working
- Command-line, Cmdline. Allows to execute complex commands such as: searches by key words, searches using regular expressions, read an external file, open an external file, etc.
- Visual. Allows you to select a block of text in a simple and flexible way and execute operations such as: delete, copy, change to upper case or to lower case as applicable, space to the right, to the left, etc.
- Select. Similar to selection mode implemented by OpenOffice/LibreOffice by typing a printable character delete the selection and starts the insert mode
- Ex. Similar to the Cmdline mode, but after running a command mode remains
| From / to | Normal | Insert | Cmdline | Visual | Select | Ex |
| Normal | i, Shift i | :, /, ?, ! | v, Shift v, Ctrl v | gh, g Shift h, g Ctrl h | Shift q | |
| Insert | Esc | — | — | — | — | |
| Cmdline | Enter, Esc, Ctrl c | :start | — | — | — | |
| Visual | Esc, v | c, Shift c | : | Ctrl g | — | |
| Select | * | ** | — | Ctrl o, Ctrl g | — | |
| Ex | :vi | — | — | — | — |
* You can change from Select selection to Normal mode pressing one of the buttons ← → ↑ ↓
** You can enter in insert mode holding any printable character
Relevant characteristics
- Highlighting of syntax for more than 200 programming languages (Java, Perl, PHP, Python, Bash, etc.)
- Integration with a large number of compilers, interpreters and debuggers (GCC, MANX AZTEC C, TEX COMPILER, other)
- Autocomplete
- Search by key words
- Allows to execute operations (searches, substitutions of words) based on regular expressions
- Undo and redo
- Command completion (similar to bash)
- Horizontal, vertical, or multiple windows which allow you to edit various file at the same time
- Flexible architecture that allows the integration of additional functionality through scripts developed by contributors
- Online documentation and integrated to the editor
Vim also has a user interface (gVim), which may be more friendly for beginners, however veterans administrators prefer use it in text mode
The latest stable version is the 7.4.x Also the binary is available for the following platforms: UNIX, MS-DOS / MS-Windows, Macintosh, Amiga, OS/2, Cygwin, other.
Further reading
Schulz, Kim. Hacking Vim
http://en.wikipedia.org/wiki/Vim
Change keyboard layout in KDE
How to change the configuration of my keyboard in KDE to be able to write accented words?
Use the following procedure to change the setting of your keyboard in KDE.
What is new in PHP 5.5?
In recent years the PHP community has made a great effort to improving and adding new features and functionality to this popular programming language in order to make it more attractive, functional and useful. With the release of PHP 5.5 have been introduced some features very expected by the developer community. Today LibreByte proposes to show everything new which brings PHP 5.5.