Update

unix_philosophy.md

@@ -20,19 +20,22 @@ Details such as to what extent/extreme this minimalism ("doing only one thing")
 **Simple example**: maybe the most common practical example that can be given is [piping](pipe.md) small [command line](cli.md) utility programs; in Unix there exist a number of small programs that do *only one thing but do it well*, for example the [`cat`](cat.md) program that only concatenates and outputs the content of selected files, the [`grep`](grep.md) program that searches for patterns in text etc. In a command line we may use so called [pipes](pipe.md) to chain some of these simple programs into more complex processing pipelines by redirecting one program's output stream to another one's input. Let's say we want to for example automatically list all first and second level headings on given webpage and write them out alphabetically sorted. We can do it with a command such as this one:
 
 ```
-curl "https://www.tastyfish.cz/lrs/main.html" | grep "<h[12]>.*</h[12]>" | sed "s/[^>]*> *\([^<]*\) *<.*/\1/g" | sort
+wget -q -O - "http://www.tastyfish.cz/lrs/main.html" | grep -i -o "<h[12][^>]*>[^<]*<" | sed "s/[^>]*> *\([^ ][^<]*[^ ]\) *<.*/\1/g" | sort
 ```
 
 Which may output for example:
 
 ```
 Are You A Noob?
-Some Interesting Topics
+Did You Know
+less_retarded_wiki
+Topics
+Wanna Help?
 Welcome To The Less Retarded Wiki
-What Is Less Retarded Software
+What Is Less Retarded Software/Society/Wiki?
 ```
 
-In the command the pipes (`|`) chain multiple programs together so that the output of one becomes the input of the next. The first command, [`curl`](curl.md), downloads the [HTML](html.md) content of the webpage and passes it to the second command, [`grep`](grep.md), which filters the text and only prints lines with headings, this is passed to [`sed`](sed.md) that removes the HTML code and the result is passed to `sort` that sorts the lines alphabetically -- as this is the last command, the result is then printed out. This is fast, powerful and very flexible way of processing data for anyone who knows the Unix tools. Notice the relative simplicity of each command and how each one works as a **[text](text.md) [filter](filter.md)**; text is a universal communication interface and behaving as a filter makes intercommunication easy and efficient. A filter simply takes an input stream of data and outputs another stream of data; it ideally works on-the-go (without having to load whole input in order to produce the output), which has great many advantages, for example requiring only a small amount of memory (which may become significant when we are running many programs at once in the pipeline) and decreasing [latency](latency.md) (the next pipe stage may start processing the data before the previous stage finishes). When you're writing a program, such as for example a [compression](compression.md) tool, make it work like this.
+In the command the pipes (`|`) chain multiple programs together so that the output of one becomes the input of the next. The first command, *[wget](wget.md)*, downloads the [HTML](html.md) content of the webpage and passes it to the second command, *[grep](grep.md)*, which filters the text and only prints lines with headings (using so called [regular expressions](regex.md)), this is passed to *[sed](sed.md)* that removes the HTML code and the result is passed to *sort* that sorts the lines alphabetically -- as this is the last command, the result is then printed out, but we could also e.g. add ` > output.txt` at the end to save the result into a text file instead. We also use [flags](flag.md) to modify the behavior of the programs, for example `-i` tells *grep* to work in case-insensitive mode, `-q` tells *wget* to be silent and not print things such as download progress. [This whole wiki](lrs_wiki.md) is basically made on top of a few scripts like this (compare e.g. to [MediaWiki](mediawiki.md) software), so you literally see the manifestation of these presented concepts as you're reading this. This kind of "workflow" is a fast, powerful and very flexible way of processing data for anyone who knows the Unix tools. Notice the relative simplicity of each command and how each one works as a **[text](text.md) [filter](filter.md)**; text is a universal communication interface and behaving as a filter makes intercommunication easy and efficient, utilizing the principle of a [pipeline](pipeline.md). A filter simply takes an input stream of data and outputs another stream of data; it ideally works on-the-go (without having to load whole input in order to produce the output), which has numerous advantages, for example requiring only a small amount of memory (which may become significant when we are running many programs at once in the pipeline, imagine e.g. a server with 10000 users, each one running his own commands like this) and decreasing [latency](latency.md) (the next pipe stage may start processing the data before the previous stage finishes). When you're writing a program, such as for example a [compression](compression.md) tool, make it work like this.
 
 Compare this to the opposite [Windows philosophy](windows_philosophy.md) in which combining programs into collaborating units is not intended, is possibly even purposefully prevented and therefore very difficult, slow and impractical to do -- such programs are designed for manually performing some predefined actions, mostly using [GUI](gui.md), e.g. painting pictures with a mouse, but aren't made to collaborate or be automatized, they can rarely be used in unintended, inventive ways needed for powerful [hacking](hacking.md). Getting back to the example of a compression tool, on Windows such a program would be a large GUI program that requires a user to open up a file dialog, manually select a file to compress, which would then probably go on to load the whole file into memory, perform compression there, and the write the data back to some other file. Need to use the program on a computer without graphical display? Automatize it to work with other programs? Run it from a script? Run it 10000 at the same time with 10000 other similar programs? Bad luck, Windows philosophy doesn't allow this.