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Michael Murtaugh: /* Examples of wget */

2008-12-03T14:21:01Z

Examples of wget

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== Command Line Media / "Media Bashing" ==

While the command line, or shell, is a text-based interface, this does not mean that manipulating other kinds of media, image, sound, video, is excluded. Far from it, many command line tools offer extremely useful and uniquely powerful functionality difficult to achieve with [[GUI]] programs. In addition, by applying the basics of [[pipeline | pipelining]] and [[abstraction]] (through creating your own scripts with parameters), the command line enables highly particular and personal media tools to be created by pulling existing tools together in novel ways.

Considering the difference between graphical / interactive software and textual / non-interactive, you could compare:

{| class=border
|graphical / interactive
|command-line / non-interactive
|-
|the [[GIMP]] or Photoshop
|[[ImageMagick]]
|-
|[[FireFox]]
|[[wget]]
|-
|Cinelerra or Final Cut
|[[ffmpeg]]
|}

So the difference is not simply whether a program uses graphics or not -- Command-line programs are designed to perform a very specific task, and typically are specified textually according to a strict syntax (command-line options, etc.) They are non-interactive in the sense that you start them up, they do their thing, and you get the result -- you don't typically influence them while they are running. However, you often can work interactively with these programs through cycles of making changes to a script, running it, observing the result and repeating.

== Making a "frontpage" snapshot tool ==

An exercise to build a simple tool to support visual comparison of front pages newssites a la Sarah Charlesworth's [http://www.sarahcharlesworth.net/series-view.php?album_id=34&subalbum_id=53 Modern History] (1978). The work, among many other works of interest, can be seen as part of the [http://www.muhka.be/toont_beeldende_kunst_detail.php?la=en&id=2590&subbase=actueel&jaartal= Order Of Things] exhibition until Jan 4, 2009 at the MuKHA, Antwerp.

Exercise explores the principle of:
* simple command line tools focused on doing a simple task
* the idea of a pipeline to join various commands together
* introducing the concept of a variable to make a personal "tool"
* cron jobs to automate a process over a long time period

== Tutorial ==

=== Getting a grip on a tool ===

Command line programs, as focused and "simple" as they may be, often take some time to get used to. The initial man-page dump of possible options may seem overwhelming at first, but if you simply have a little discipline to try some variations, and above all to record your successes (in a text file and/or by taking notes on a printed copy of a man page), you can soon feel comfortable to use the new program.

We start with the tool [[wget]].

First, simply try to run it:

<source lang="bash">
wget
</source>

<source lang="bash">
wget --help
</source>

Too much information! A [[pipeline]] to the rescue!

<source lang="bash">
wget --help | less
</source>

<source lang="bash">
man wget
</source>

Man has an option to output print-friendly postscript output. It's described on the "man" man page. (That's right: "man man"!)

<source lang="bash">
man -t wget
</source>

<source lang="bash">
man -t wget > wget.ps
</source>

Now you can print the postscript file, or view with a viewer like evince:

<source lang="bash">
evince wget.ps
</source>

=== Necessary Tools / Topics ===
* Shell basics: cd, pwd, mv, cp
* Connecting to a "remote" server with ssh
* public_html
* scp
* [[wget]]
* [[ImageMagick]]: montage

=== Concepts ===
* man pages
* command line options

=== Examples of wget ===

Start from these examples, culled from the web. Try the examples out, alter the options. Find the options used in the (printed) man page of wget. Collect working (or interesting non-working) commands in a text file, and add comments to remind yourself why they were noteworthy.

* http://linuxgazette.net/issue70/chung.html
* http://tipotheday.com/2007/10/11/wget-some-quick-tips/
* http://ubuntuforums.org/showthread.php?t=718549&page=2

To download all the files in a "directory listing":
<source lang="bash">
wget -r -np -nd http://example.com/packages/
</source>

=== Solutions ===

<source lang="bash">
wget -r -nd -np --follow-tags=img http://www.colourlovers.com -A.jpg,.jpeg
montage *.jpg ../public_html/montage.jpg
</source>

Blurps out this file: http://pzwart2.wdka.hro.nl/~tklok/montage.jpg

(Notice the wget is run from a different directory the where the picture is placed)

*http://pzwart2.wdka.hro.nl/~ebonetti/Emanuele/montage.png

*http://pzwart2.wdka.hro.nl/~svilayphiou/techdaze/102/montage.jpg

*http://pzwart2.wdka.hro.nl/~cbaronavski/static/hate.jpg

== Assignment for next week ==

* Chapters 3 & 4 from [[Think Python]]
* Exercises from the book plus the [[Think Python X3 | additional exercise]]

Chapter 4 introduces some [[Turtle Graphics]]!

Michael Murtaugh at 09:51, 15 October 2008

2008-10-15T09:51:44Z

← Older revision		Revision as of 11:51, 15 October 2008
Line 1:		Line 1:
	~~[[Image:Construction.gif]]~~
	~~this page is under construction ;)~~

	== Command Line Media / "Media Bashing" ==		== Command Line Media / "Media Bashing" ==

Michael Murtaugh: /* Examples of wget */

2008-10-14T16:28:51Z

Examples of wget

← Older revision		Revision as of 18:28, 14 October 2008
Line 91:		Line 91:

	=== Examples of wget ===		=== Examples of wget ===

			Start from these examples, culled from the web. Try the examples out, alter the options. Find the options used in the (printed) man page of wget. Collect working (or interesting non-working) commands in a text file, and add comments to remind yourself why they were noteworthy.

	* http://linuxgazette.net/issue70/chung.html		* http://linuxgazette.net/issue70/chung.html

Michael Murtaugh: /* Command Line Media / "Media Bashing" */

2008-10-14T16:24:07Z

Command Line Media / "Media Bashing"

← Older revision		Revision as of 18:24, 14 October 2008
Line 17:		Line 17:
	\|[[FireFox]]		\|[[FireFox]]
	\|[[wget]]		\|[[wget]]
			\|-
			\|Cinelerra or Final Cut
			\|[[ffmpeg]]
	\|}		\|}

Michael Murtaugh: /* Command Line Media / "Media Bashing" */

2008-10-14T16:23:16Z

Command Line Media / "Media Bashing"

← Older revision		Revision as of 18:23, 14 October 2008
Line 18:		Line 18:
	\|[[wget]]		\|[[wget]]
	\|}		\|}

			So the difference is not simply whether a program uses graphics or not -- Command-line programs are designed to perform a very specific task, and typically are specified textually according to a strict syntax (command-line options, etc.) They are non-interactive in the sense that you start them up, they do their thing, and you get the result -- you don't typically influence them while they are running. However, you often can work interactively with these programs through cycles of making changes to a script, running it, observing the result and repeating.

	== Making a "frontpage" snapshot tool ==		== Making a "frontpage" snapshot tool ==

Michael Murtaugh: /* Command Line Media / "Media Bashing" */

2008-10-14T16:17:32Z

Command Line Media / "Media Bashing"

← Older revision		Revision as of 18:17, 14 October 2008
Line 8:		Line 8:
	Considering the difference between graphical / interactive software and textual / non-interactive, you could compare:		Considering the difference between graphical / interactive software and textual / non-interactive, you could compare:

	{\|		{\| class=border
	\|graphical / interactive		\|graphical / interactive
	\|command-line / non-interactive		\|command-line / non-interactive

Michael Murtaugh: /* Command Line Media / "Media Bashing" */

2008-10-14T16:17:21Z

Command Line Media / "Media Bashing"

← Older revision		Revision as of 18:17, 14 October 2008
Line 5:		Line 5:

	While the command line, or shell, is a text-based interface, this does not mean that manipulating other kinds of media, image, sound, video, is excluded. Far from it, many command line tools offer extremely useful and uniquely powerful functionality difficult to achieve with [[GUI]] programs. In addition, by applying the basics of [[pipeline \| pipelining]] and [[abstraction]] (through creating your own scripts with parameters), the command line enables highly particular and personal media tools to be created by pulling existing tools together in novel ways.		While the command line, or shell, is a text-based interface, this does not mean that manipulating other kinds of media, image, sound, video, is excluded. Far from it, many command line tools offer extremely useful and uniquely powerful functionality difficult to achieve with [[GUI]] programs. In addition, by applying the basics of [[pipeline \| pipelining]] and [[abstraction]] (through creating your own scripts with parameters), the command line enables highly particular and personal media tools to be created by pulling existing tools together in novel ways.

			Considering the difference between graphical / interactive software and textual / non-interactive, you could compare:

			{\|
			\|graphical / interactive
			\|command-line / non-interactive
			\|-
			\|the [[GIMP]] or Photoshop
			\|[[ImageMagick]]
			\|-
			\|[[FireFox]]
			\|[[wget]]
			\|}

	== Making a "frontpage" snapshot tool ==		== Making a "frontpage" snapshot tool ==

Michael Murtaugh: /* Necessary Tools / Topics */

2008-10-14T16:14:49Z

Necessary Tools / Topics

← Older revision		Revision as of 18:14, 14 October 2008
Line 66:		Line 66:
	* scp		* scp
	* [[wget]]		* [[wget]]
	* [[ImageMagick]]: ~~convert, mogrify,~~ montage		* [[ImageMagick]]: montage

	=== Concepts ===		=== Concepts ===

Michael Murtaugh: /* Getting a grip on a tool */

2008-10-14T16:14:30Z

Getting a grip on a tool

← Older revision		Revision as of 18:14, 14 October 2008
Line 53:		Line 53:
	man -t wget > wget.ps		man -t wget > wget.ps
	</source>		</source>

			Now you can print the postscript file, or view with a viewer like evince:

	<source lang="bash">		<source lang="bash">
	evince wget.ps		evince wget.ps
	</source>		</source>


	=== Necessary Tools / Topics ===		=== Necessary Tools / Topics ===

Michael Murtaugh: /* Making a "frontpage" snapshot tool */

2008-10-14T16:13:34Z

Making a "frontpage" snapshot tool

← Older revision		Revision as of 18:13, 14 October 2008
Line 8:		Line 8:
	== Making a "frontpage" snapshot tool ==		== Making a "frontpage" snapshot tool ==

	An exercise to build a simple tool to support visual comparison of front pages newssites a la Sarah Charlesworth's [http://www.sarahcharlesworth.net/series-view.php?album_id=34&subalbum_id=53 Modern History] (1978). The work, among many other works of interest, can be seen as part of the [http://www.muhka.be/toont_beeldende_kunst_detail.php?la=en&id=2590&subbase=actueel&jaartal= Order Of Things] exhibition, ~~through the end of the year~~ at the MuKHA, Antwerp.		An exercise to build a simple tool to support visual comparison of front pages newssites a la Sarah Charlesworth's [http://www.sarahcharlesworth.net/series-view.php?album_id=34&subalbum_id=53 Modern History] (1978). The work, among many other works of interest, can be seen as part of the [http://www.muhka.be/toont_beeldende_kunst_detail.php?la=en&id=2590&subbase=actueel&jaartal= Order Of Things] exhibition until Jan 4, 2009 at the MuKHA, Antwerp.

	Exercise explores the principle of:		Exercise explores the principle of: