Browse Source

working scripts; bash ranting; stub new chapter

Also adds a few dependencies to Makefile, comments out some formatting
in render.pl, sets up a demonstration of converting a program from
specific -> general, perhaps lays groundwork for a discussion of the
utility of diff(1) in software terms, which seems like a good transition
back to extant literary tooling.
master
Brennen Bearnes 11 years ago
parent
commit
4632a736bc
12 changed files with 436 additions and 168 deletions
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@ -2,5 +2,5 @@ chapters = $(shell cat chapters)
all: index.html
index.html: ${chapters} chapters
index.html: ${chapters} chapters render.pl footer.html header.html
cat chapters | xargs perl ./render.pl | cat header.html - footer.html > $@

+ 2
- 1
chapters View File

@ -2,7 +2,8 @@
./literary_environment/index.md
./literary_problem/index.md
./programmerthink/index.md
./programs/index.md
./script/index.md
./general_purpose/index.md
./diff/index.md
./further_reading/index.md
./links.md

+ 1
- 1
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@ -1,4 +1,4 @@
4. diff, wdiff, git
6. diff, wdiff, git
===================
If you're the sort of person who took a few detours into the history of


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- 0
general_purpose/index.md View File

@ -0,0 +1,4 @@
5. general purpose programmering
================================

+ 174
- 64
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@ -59,14 +59,16 @@ in my own work.</p>
</li>
<li><a href="#a-literary-problem">2. a literary problem</a></li>
<li><a href="#programmerthink">3. programmerthink</a></li>
<li><a href="#programs-programmering">4. programs + programmering</a>
<li><a href="#script">4. script</a>
<ul>
<li><a href="#learn-you-an-editor">learn you an editor</a></li>
<li><a href="#scripting">scripting</a></li>
<li><a href="#d-i-y-utilities">d.i.y. utilities</a></li>
<li><a href="#a-confession">a confession</a></li>
</ul>
</li>
<li><a href="#diff-wdiff-git">4. diff, wdiff, git</a></li>
<li><a href="#general-purpose-programmering">5. general purpose programmering</a></li>
<li><a href="#diff-wdiff-git">6. diff, wdiff, git</a></li>
<li><a href="#further-reading">further reading</a>
<ul>
@ -170,7 +172,7 @@ instead of navigating around virtual rooms and hallways with commands like
<code>LOOK</code> and <code>EAST</code>, you navigate between directories by typing commands like
<code>ls</code> and <code>cd notes</code>:</p>
<pre><code><b>$ ls</b>
<pre><code>$ ls
code Downloads notes p1k3 photos scraps userland-book
$ cd notes
$ ls
@ -207,7 +209,7 @@ comes in:</p>
<!-- exec -->
<pre><code><b>$ cat authors_sff</b>
<pre><code>$ cat authors_sff
Ursula K. Le Guin
Jo Walton
Pat Cadigan
@ -234,7 +236,7 @@ simple actions.</p>
<!-- exec -->
<pre><code><b>$ cat authors_sff authors_contemporary_fic authors_nat_hist</b>
<pre><code>$ cat authors_sff authors_contemporary_fic authors_nat_hist
Ursula K. Le Guin
Jo Walton
Pat Cadigan
@ -261,7 +263,7 @@ something to all three files. Fortunately, our shell offers a shorthand for
<!-- exec -->
<pre><code><b>$ cat authors_*</b>
<pre><code>$ cat authors_*
Eden Robinson
Vanessa Veselka
Miriam Toews
@ -294,7 +296,7 @@ Here&rsquo;s a command that will give us some organization:</p>
<!-- exec -->
<pre><code><b>$ sort authors_*</b>
<pre><code>$ sort authors_*
Eden Robinson
Gwendolyn L. Waring
James Tiptree, Jr.
@ -318,7 +320,7 @@ key (by default, sort treats whitespace as a division between fields):</p>
<!-- exec -->
<pre><code><b>$ sort -k2 authors_*</b>
<pre><code>$ sort -k2 authors_*
John Brunner
Pat Cadigan
Ursula K. Le Guin
@ -351,7 +353,7 @@ of authors. Let&rsquo;s make sure our list doesn&rsquo;t contain repeating line
<!-- exec -->
<pre><code><b>$ sort -k2 authors_* | uniq</b>
<pre><code>$ sort -k2 authors_* | uniq
John Brunner
Pat Cadigan
Ursula K. Le Guin
@ -392,7 +394,7 @@ count of how often each line occurs, for a file called colors:</p>
<!-- exec -->
<pre><code><b>$ cat colors</b>
<pre><code>$ cat colors
RED
blue
red
@ -411,7 +413,7 @@ GREEN
<!-- exec -->
<pre><code><b>$ sort colors | uniq -i -c</b>
<pre><code>$ sort colors | uniq -i -c
2 blue
3 green
2 red
@ -447,7 +449,7 @@ the input of another, you&rsquo;d like to just stash it in a file for later use?
<!-- exec -->
<pre><code><b>$ sort authors_* | uniq &gt; all_authors</b>
<pre><code>$ sort authors_* | uniq &gt; all_authors
</code></pre>
<!-- end -->
@ -458,7 +460,7 @@ the input of another, you&rsquo;d like to just stash it in a file for later use?
<!-- exec -->
<pre><code><b>$ cat all_authors</b>
<pre><code>$ cat all_authors
Eden Robinson
Gwendolyn L. Waring
James Tiptree, Jr.
@ -480,7 +482,7 @@ program?</p>
<!-- exec -->
<pre><code><b>$ nl &lt; all_authors</b>
<pre><code>$ nl &lt; all_authors
1 Eden Robinson
2 Gwendolyn L. Waring
3 James Tiptree, Jr.
@ -512,7 +514,7 @@ certain utility takes, but what if you don&rsquo;t?</p>
<p>What you want is called a man (short for manual) page. (It&rsquo;s sort of an
unfortunate abbreviation.)</p>
<pre><code><b>$ man sort</b>
<pre><code>$ man sort
SORT(1) User Commands SORT(1)
@ -532,7 +534,7 @@ DESCRIPTION
<p>&hellip;and so on. You can also ask a lot of commands directly for help on how to
use them:</p>
<pre><code><b>$ uniq --help</b>
<pre><code>$ uniq --help
Usage: uniq [OPTION]... [INPUT [OUTPUT]]
Filter adjacent matching lines from INPUT (or standard input),
writing to OUTPUT (or standard output).
@ -552,7 +554,7 @@ have]&hellip;&rdquo;</p>
<!-- exec -->
<pre><code><b>$ apropos sort</b>
<pre><code>$ apropos sort
alphasort (3) - scan a directory for matching entries
apt-sortpkgs (1) - Utility to sort package index files
bsearch (3) - binary search of a sorted array
@ -588,7 +590,7 @@ literary traditions, Unix is littered with this sort of convention.</p>
<p><code>wc</code> stands for <strong>w</strong>ord <strong>c</strong>ount. It does about what you&rsquo;d expect - it
counts the number of words in its input.</p>
<pre><code><b>$ wc index.md</b>
<pre><code>$ wc index.md
736 4117 24944 index.md
</code></pre>
@ -598,14 +600,14 @@ obviously, it&rsquo;s a good way to get an idea of how much you&rsquo;ve written
the tool I used to track my progress the last time I tried National Novel
Writing Month:</p>
<pre><code><b>$ find ~/p1k3/archives/2010/11 -regextype egrep -regex '.*([0-9]+|index)' -type f | xargs wc -w | grep total</b>
<pre><code>$ find ~/p1k3/archives/2010/11 -regextype egrep -regex '.*([0-9]+|index)' -type f | xargs wc -w | grep total
6585 total
</code></pre>
<!-- exec -->
<pre><code><b>$ cowsay 'embarrassing.'</b>
<pre><code>$ cowsay 'embarrassing.'
_______________
&lt; embarrassing. &gt;
---------------
@ -625,7 +627,7 @@ output of other commands. Want to know <em>how many</em> unique authors we have
<!-- exec -->
<pre><code><b>$ sort authors_* | uniq | wc -l</b>
<pre><code>$ sort authors_* | uniq | wc -l
10
</code></pre>
@ -654,7 +656,7 @@ CDs.</p>
<p>So. Want to know the definition of a word, or find useful synonyms?</p>
<pre><code><b>$ dict concatenate | head -10</b>
<pre><code>$ dict concatenate | head -10
4 definitions found
From The Collaborative International Dictionary of English v.0.48 [gcide]:
@ -669,12 +671,12 @@ From The Collaborative International Dictionary of English v.0.48 [gcide]:
<p>Need to interactively spell-check your presentation notes?</p>
<pre><code><b>$ aspell check presentation</b>
<pre><code>$ aspell check presentation
</code></pre>
<p>Want to know what the calendar looks like for this month?</p>
<pre><code><b>$ cal</b>
<pre><code>$ cal
April 2014
Su Mo Tu We Th Fr Sa
1 2 3 4 5
@ -689,7 +691,7 @@ Su Mo Tu We Th Fr Sa
<!-- exec -->
<pre><code><b>$ cal -m9 1950</b>
<pre><code>$ cal -m9 1950
September 1950
Su Mo Tu We Th Fr Sa
1 2
@ -714,7 +716,7 @@ file:</p>
<!-- exec -->
<pre><code><b>$ head -3 colors</b>
<pre><code>$ head -3 colors
RED
blue
red
@ -728,7 +730,7 @@ red
<!-- exec -->
<pre><code><b>$ sort colors | uniq -i | tail -1</b>
<pre><code>$ sort colors | uniq -i | tail -1
red
</code></pre>
@ -742,7 +744,7 @@ return only the first field for each line of its input:</p>
<!-- exec -->
<pre><code><b>$ cut -d' ' -f1 ./authors_*</b>
<pre><code>$ cut -d' ' -f1 ./authors_*
Eden
Vanessa
Miriam
@ -767,7 +769,7 @@ writing in real life:</p>
<!-- exec -->
<pre><code><b>$ cut -d' ' -f1 ./authors_* | sort | uniq -ci | sort -n | tail -3</b>
<pre><code>$ cut -d' ' -f1 ./authors_* | sort | uniq -ci | sort -n | tail -3
1 Ursula
2 John
2 Vanessa
@ -811,7 +813,7 @@ you could instead do:</p>
<!-- exec -->
<pre><code><b>$ sort -u ./authors_* | cut -d' ' -f1 | uniq -ci | sort -n | tail -3</b>
<pre><code>$ sort -u ./authors_* | cut -d' ' -f1 | uniq -ci | sort -n | tail -3
1 Ursula
1 Vanessa
2 John
@ -828,7 +830,7 @@ an individual author appears on?</p>
<!-- exec -->
<pre><code><b>$ grep 'Vanessa' ./authors_*</b>
<pre><code>$ grep 'Vanessa' ./authors_*
./authors_contemporary_fic:Vanessa Veselka
./authors_sff:Vanessa Veselka
</code></pre>
@ -842,7 +844,7 @@ in. If you don&rsquo;t specify files, it&rsquo;ll look through standard input
<!-- exec -->
<pre><code><b>$ cat ./authors_* | grep 'Vanessa'</b>
<pre><code>$ cat ./authors_* | grep 'Vanessa'
Vanessa Veselka
Vanessa Veselka
</code></pre>
@ -878,7 +880,7 @@ shell to match groups of files, but with more magic.</p>
<!-- exec -->
<pre><code><b>$ grep 'Jo.*' ./authors_*</b>
<pre><code>$ grep 'Jo.*' ./authors_*
./authors_sff:Jo Walton
./authors_sff:John Ronald Reuel Tolkien
./authors_sff:John Brunner
@ -921,7 +923,7 @@ means that lots of characters will have special meanings.</p>
<!-- exec -->
<pre><code><b>$ grep -iE '^[a-z]{4} ' ./authors_*</b>
<pre><code>$ grep -iE '^[a-z]{4} ' ./authors_*
./authors_contemporary_fic:Eden Robinson
./authors_sff:John Ronald Reuel Tolkien
./authors_sff:John Brunner
@ -935,7 +937,7 @@ means that lots of characters will have special meanings.</p>
<!-- exec -->
<pre><code><b>$ grep -c '^John ' ./all_authors</b>
<pre><code>$ grep -c '^John ' ./all_authors
2
</code></pre>
@ -944,7 +946,7 @@ means that lots of characters will have special meanings.</p>
<p>Lines in this file matching the words &ldquo;magic&rdquo; or &ldquo;magical&rdquo;:</p>
<pre><code><b>$ grep -iE 'magic(al)?' ./index.md</b>
<pre><code>$ grep -iE 'magic(al)?' ./index.md
Pipes are some of the most important magic in the shell. When the people who
shell to match groups of files, but with more magic.
`.` and `*` are magical. In the particular dialect of regexen understood
@ -959,7 +961,7 @@ Lines in this file matching the words "magic" or "magical":
<!-- exec -->
<pre><code><b>$ grep -iE '(m|tr|pel)agic' /usr/share/dict/words</b>
<pre><code>$ grep -iE '(m|tr|pel)agic' /usr/share/dict/words
magic
magic's
magical
@ -1018,7 +1020,7 @@ the least-embarrassing stuff into a single collection.</p>
<p>I&rsquo;ve hinted at how the contents of my blog are stored as files, but let&rsquo;s take
a look at the whole thing:</p>
<pre><code><b>$ ls -F ~/p1k3/archives/</b>
<pre><code>$ ls -F ~/p1k3/archives/
1997/ 2003/ 2009/ bones/ meta/
1998/ 2004/ 2010/ chapbook/ winfield/
1999/ 2005/ 2011/ cli/ wip/
@ -1044,7 +1046,7 @@ March 1st:</p>
<!-- exec -->
<pre><code><b>$ cat ~/p1k3/archives/2014/3/1</b>
<pre><code>$ cat ~/p1k3/archives/2014/3/1
&lt;h1&gt;Saturday, March 1&lt;/h1&gt;
&lt;markdown&gt;
@ -1063,7 +1065,7 @@ with an actual keyboard. It's almost certainly for the best.
<!-- exec -->
<pre><code><b>$ cat ~/p1k3/archives/2012/10/9</b>
<pre><code>$ cat ~/p1k3/archives/2012/10/9
&lt;h1&gt;tuesday, october 9&lt;/h1&gt;
&lt;freeverse&gt;i am a stateful machine
@ -1083,7 +1085,7 @@ want to do is get a list of all the entries that contain poems.</p>
<p>Remember <code>grep</code>?</p>
<pre><code><b>$ grep -ri '&lt;freeverse&gt;' ~/p1k3/archives &gt; ~/possible_poems</b>
<pre><code>$ grep -ri '&lt;freeverse&gt;' ~/p1k3/archives &gt; ~/possible_poems
</code></pre>
<p>Let&rsquo;s step through this bit by bit:</p>
@ -1117,13 +1119,13 @@ called <code>possible_poems</code> in my home directory:</p>
<p>This is quite a few instances&hellip;</p>
<pre><code><b>$ wc -l ~/possible_poems</b>
<pre><code>$ wc -l ~/possible_poems
679 /home/brennen/possible_poems
</code></pre>
<p>&hellip;and it&rsquo;s also not super-pretty to look at:</p>
<pre><code><b>$ head -5 ~/possible_poems</b>
<pre><code>$ head -5 ~/possible_poems
/home/brennen/p1k3/archives/2011/10/14:&lt;freeverse&gt;i've got this friend has a real knack
/home/brennen/p1k3/archives/2011/4/25:&lt;freeverse&gt;i can't claim to strive for it
/home/brennen/p1k3/archives/2011/8/10:&lt;freeverse&gt;one diminishes or becomes greater
@ -1140,7 +1142,7 @@ to a new file.</p>
between hundreds of files, I&rsquo;d rather read everything in one file and just weed
out the bad ones as I go?</p>
<pre><code><b>$ cat `grep -ril '&lt;freeverse&gt;' ~/p1k3/archives` &gt; ~/possible_poems_full</b>
<pre><code>$ cat `grep -ril '&lt;freeverse&gt;' ~/p1k3/archives` &gt; ~/possible_poems_full
</code></pre>
<p>This probably bears some explaining. <code>grep</code> is still doing all the real work
@ -1156,14 +1158,14 @@ command, it&rsquo;ll get executed and replaced with its result, which in turn ge
executed as part of the larger command. So what we&rsquo;re really saying is
something like:</p>
<pre><code><b>$ cat [all of the files in the blog directory with &lt;freeverse&gt; in them]</b>
<pre><code>$ cat [all of the files in the blog directory with &lt;freeverse&gt; in them]
</code></pre>
<p>Did you catch that? I just wrote a command that rewrote itself as a
<em>different</em>, more specific command. And it appears to have worked on the
first try:</p>
<pre><code><b>$ wc ~/possible_poems_full</b>
<pre><code>$ wc ~/possible_poems_full
17628 80980 528699 /home/brennen/possible_poems_full
</code></pre>
@ -1241,7 +1243,7 @@ not define a directory structure for the years and months, and then write a
file to hold each day? That way, all I&rsquo;d have to do is concatenate the files
in one directory to display any given month:</p>
<pre><code><b>$ cat ~/p1k3/archives/2014/1/* | head -10</b>
<pre><code>$ cat ~/p1k3/archives/2014/1/* | head -10
&lt;h1&gt;Sunday, January 12&lt;/h1&gt;
&lt;h2&gt;the one casey is waiting for&lt;/h2&gt;
@ -1266,19 +1268,19 @@ about my blog posts or re-combine them in certain ways, I can address my
concerns to this model. Maybe, for example, I want a rough idea how many words
I&rsquo;ve written in blog posts so far in 2014:</p>
<pre><code><b>$ find ~/p1k3/archives/2014/ -type f | xargs cat | wc -w</b>
<pre><code>$ find ~/p1k3/archives/2014/ -type f | xargs cat | wc -w
6677
</code></pre>
<p><code>xargs</code> is not the most intuitive command, but it&rsquo;s useful and common enough to
explain here. At the end of last chapter, when I said:</p>
<pre><code><b>$ cat `grep -ril '&lt;freeverse&gt;' ~/p1k3/archives` &gt; ~/possible_poems_full</b>
<pre><code>$ cat `grep -ril '&lt;freeverse&gt;' ~/p1k3/archives` &gt; ~/possible_poems_full
</code></pre>
<p>I could also have written this as:</p>
<pre><code><b>$ grep -ril '&lt;freeverse&gt;' ~/p1k3/archives | xargs cat &gt; ~/possible_poems_full</b>
<pre><code>$ grep -ril '&lt;freeverse&gt;' ~/p1k3/archives | xargs cat &gt; ~/possible_poems_full
</code></pre>
<p>What this does is take its input, which starts like:</p>
@ -1308,7 +1310,7 @@ filenames, but I wind up using it quite a bit.</p>
<!-- exec -->
<pre><code><b>$ find ~/p1k3/archives/2014/ -type d | xargs ls -v | head -10</b>
<pre><code>$ find ~/p1k3/archives/2014/ -type d | xargs ls -v | head -10
/home/brennen/p1k3/archives/2014/:
1
2
@ -1329,7 +1331,7 @@ filenames, but I wind up using it quite a bit.</p>
<!-- exec -->
<pre><code><b>$ find ~/p1k3/archives/2012/ -type f | xargs perl -ne 'print "$1\n" if m{&lt;h2&gt;(.*?)&lt;/h2&gt;}'</b>
<pre><code>$ find ~/p1k3/archives/2012/ -type f | xargs perl -ne 'print "$1\n" if m{&lt;h2&gt;(.*?)&lt;/h2&gt;}'
pursuit
fragment
this poem again
@ -1420,7 +1422,7 @@ eventually arrived at this:</p>
neither my blog code nor web browsers nor my text editor have to know anything
about the format, but I can easily find files with certain values. Check it:</p>
<pre><code><b>$ find ~/p1k3/archives -type f | xargs perl -ne 'print "$ARGV[0]: $1 -&gt; $2\n" if m{&lt;!-- ([a-z]+): (.*?) --&gt;};'</b>
<pre><code>$ find ~/p1k3/archives -type f | xargs perl -ne 'print "$ARGV[0]: $1 -&gt; $2\n" if m{&lt;!-- ([a-z]+): (.*?) --&gt;};'
/home/brennen/p1k3/archives/2014/2/9: collection -&gt; ok-poems
</code></pre>
@ -1432,7 +1434,7 @@ look at, but it&rsquo;s simple and searchable.</p>
directory that can contain some structured metadata in a separate file.
Imagine something like:</p>
<pre><code><b>$ ls ~/p1k3/archives/2013/2/9</b>
<pre><code>$ ls ~/p1k3/archives/2013/2/9
index Meta
</code></pre>
@ -1442,7 +1444,7 @@ something like <code>index.html</code>. As it happens, my blog software already
this kind of file layout for entries which contain multiple parts, image files,
and so forth.</p>
<pre><code><b>$ head ~/p1k3/archives/2013/2/9/index</b>
<pre><code>$ head ~/p1k3/archives/2013/2/9/index
&lt;h1&gt;saturday, february 9&lt;/h1&gt;
&lt;freeverse&gt;
@ -1463,7 +1465,7 @@ collection: ok-poems
<p>What if I put metadata right in the filename itself, and dispense with the grep
altogether?</p>
<pre><code><b>$ ls ~/p1k3/archives/2013/2/9</b>
<pre><code>$ ls ~/p1k3/archives/2013/2/9
index meta-ok-poem
$ find ~/p1k3/archives -name 'meta-ok-poem'
@ -1489,7 +1491,7 @@ handles a given abstraction.</p>
<hr />
<h1><a name=programs-programmering href=#programs-programmering>#</a> 4. programs + programmering</h1>
<h1><a name=script href=#script>#</a> 4. script</h1>
<p>Back in chapter 1, I said that &ldquo;the way you use the computer is often just to write
little programs that invoke other programs&rdquo;. In fact, we&rsquo;ve already gone over a
@ -1499,7 +1501,7 @@ up some good examples:</p>
<!-- exec -->
<pre><code><b>$ grep -E '[a-z]+.*\| ' ../literary_environment/index.md</b>
<pre><code>$ grep -E '[a-z]+.*\| ' ../literary_environment/index.md
$ sort -k2 authors_* | uniq
$ sort colors | uniq -i -c
$ sort authors_* | uniq &gt; all_authors
@ -1555,7 +1557,7 @@ shining diamond heart.</p>
easier places to start. Nano, for example, is easy to pick up, and should be
available on most systems. To start it, just say:</p>
<pre><code><b>$ nano file</b>
<pre><code>$ nano file
</code></pre>
<p>You should see something like this:</p>
@ -1570,19 +1572,23 @@ so <code>^O</code> means Ctrl-o (the case of the letter doesn&rsquo;t actually m
will save the file you&rsquo;re working on. Ctrl-x will quit, which is probably the
first important thing to know about any given editor.</p>
<h2><a name=scripting href=#scripting>#</a> scripting</h2>
<h2><a name=d-i-y-utilities href=#d-i-y-utilities>#</a> d.i.y. utilities</h2>
<p>So back to putting commands in text files.</p>
<p>{much verbiage about scripts to come}</p>
<!-- exec -->
<pre><code><b>$ cat lspoems</b>
<pre><code>$ cat okpoems
#!/bin/bash
# find all the marker files and get the name of
# the directory containing each
find ~/p1k3/archives -name 'meta-ok-poem' | xargs dirname
exit 0
</code></pre>
<!-- end -->
@ -1593,16 +1599,120 @@ find ~/p1k3/archives -name 'meta-ok-poem' | xargs dirname
<!-- exec -->
<pre><code><b>$ ./lspoems</b>
<pre><code>$ ./okpoems
/home/brennen/p1k3/archives/2013/2/9
/home/brennen/p1k3/archives/2012/3/17
/home/brennen/p1k3/archives/2012/3/26
</code></pre>
<!-- end -->
<!-- exec -->
<pre><code>$ cat markpoem
#!/bin/bash
# $1 is the first parameter to our script
POEM=$1
# Complain and exit if we weren't given a path:
if [ ! $POEM ]
then
echo 'usage: markpoem &lt;path&gt;'
# Confusingly, an exit status of 0 means to the shell that everything went
# fine, while any other number means that something went wrong.
exit 64
fi
if [ ! -e $POEM ]
then
echo "$POEM not found"
exit 66
fi
echo "marking $1 an ok poem"
POEM_BASENAME=$(basename $POEM)
# If the target is a plain file instead of a directory, make it into
# a directory and move the content into $POEM/index:
if [ -f $POEM ]
then
echo "making $POEM into a directory, moving content to"
echo " $POEM/index"
TEMPFILE="/tmp/$POEM_BASENAME.$(date +%s.%N)"
mv $POEM $TEMPFILE
mkdir $POEM
mv $TEMPFILE $POEM/index
fi
if [ -d $POEM ]
then
# touch(1) will either create the file or update its timestamp:
touch $POEM/meta-ok-poem
else
echo "something broke - why isn't $POEM a directory?"
file $POEM
fi
# Signal that all is copacetic:
echo kthxbai
exit 0
</code></pre>
<!-- end -->
<p>These are imperfect, but they were quick to write, they&rsquo;re made out of standard
commands, and I don&rsquo;t yet hate myself for them. These are all signs that I&rsquo;m
not totally on the wrong track with the <code>meta-ok-poem</code> abstraction, and could
build it into my ongoing writing project. These scripts would also be easy to
hook into with custom keybindings in my editor. With a few more lines of code,
I can build a system to wade through the list of candidate files one at a time
and mark the interesting ones.</p>
<h2><a name=a-confession href=#a-confession>#</a> a confession</h2>
<p>I kind of hate shell scripts, and I think it&rsquo;s ok if you hate them too.</p>
<p>That doesn&rsquo;t mean you shouldn&rsquo;t <em>know</em> about them, or that you shouldn&rsquo;t
<em>write</em> them. I write little tiny ones all the time, and the ability to read
other people&rsquo;s scripts comes in handy. Oftentimes, the best, most tasteful way
to automate something is to build a script out of the commonly available
commands. They&rsquo;re already there on millions of machines. Many of them have
been pretty well understood for a generation, and most of them will probably be
around for a generation or three to come. They do neat stuff. Scripts let you
build on the things you&rsquo;ve already figured out on the command line, and give
repeatable operations a memorable, user-friendly name.</p>
<p>One of the reliable markers of powerful software is that it can be scripted: It
extends to its users some of the same power that its authors used in creating
it. Scriptable software is to some extent <em>living</em> software. It&rsquo;s a book that
you, the reader, get to help write.</p>
<p>In all these ways, shell scripts are wonderful, and a little bit magical, and
actually, quietly indispensable to the machinery of modern civilization.</p>
<p>Unfortunately, in all the ways that a shell like Bash itself is ugly, finicky,
and covered in 40 years of weird, incidental cruft, long-form Bash scripts are
even worse. Bash is a useful glue language, particularly for things composed
in the flow of work on the command line. Syntactic and conceptual innovations
like pipes are beautiful and necessary. What Bash is <em>not</em>, despite its power,
is a very good general purpose programming language. It turns out those are
really nice to have at your disposal.</p>
<hr />
<h1><a name=general-purpose-programmering href=#general-purpose-programmering>#</a> 5. general purpose programmering</h1>
<hr />
<h1><a name=diff-wdiff-git href=#diff-wdiff-git>#</a> 4. diff, wdiff, git</h1>
<h1><a name=diff-wdiff-git href=#diff-wdiff-git>#</a> 6. diff, wdiff, git</h1>
<p>If you&rsquo;re the sort of person who took a few detours into the history of
religion in college, you might be familiar with some of the ways people used to


+ 0
- 100
programs/index.md View File

@ -1,100 +0,0 @@
4. programs + programmering
===========================
Back in chapter 1, I said that "the way you use the computer is often just to write
little programs that invoke other programs". In fact, we've already gone over a
bunch of these. Grepping through the text of a previous chapter should pull
up some good examples:
<!-- exec -->
$ grep -E '[a-z]+.*\| ' ../literary_environment/index.md
$ sort -k2 authors_* | uniq
$ sort colors | uniq -i -c
$ sort authors_* | uniq > all_authors
thing as `cat all_authors | nl`, or `nl all_authors`. You won't see this as
$ find ~/p1k3/archives/2010/11 -regextype egrep -regex '.*([0-9]+|index)' -type f | xargs wc -w | grep total
$ sort authors_* | uniq | wc -l
$ dict concatenate | head -10
$ sort colors | uniq -i | tail -1
$ cut -d' ' -f1 ./authors_* | sort | uniq -ci | sort -n | tail -3
$ sort -u ./authors_* | cut -d' ' -f1 | uniq -ci | sort -n | tail -3
$ cat ./authors_* | grep 'Vanessa'
<!-- end -->
None of these one-liners do all that much, but they all take input of one sort
or another and transform it into something new by doing a series of things to
it. They're little formal sentences describing how to make one thing into
another, which is as good a definition of programming as most. Or at least
this is a good way to describe programming-in-the-small. (A lot of the
programs we use day-to-day are more like essays, novels, or interminable
Fantasy series where every character you like dies horribly than they are like
individual sentences.)
One-liners like these are all well and good when you're staring at a terminal,
trying to figure something out - but what about when you've already figured it out and
you want to repeat it in the future?
It turns out that Bash has you covered. Since shell commands are just text,
they can live in a text file as easily as they can be typed.
learn you an editor
-------------------
We've skirted the topic so far, but now that we're talking about writing out
text files in earnest, you're going to want a text editor.
My editor is where I spend most of my time that isn't in a web browser, because
it's where I write both code and prose. It turns out that the features which
make a good code editor overlap a lot with the ones that make a good editor of
English sentences.
So what should you use? Well, there have been other contenders in recent
years, but in truth nothing comes close to dethroning the Great Old Ones of
text editing. Emacs is a creature both primal and sophisticated, like an
avatar of some interstellar civilization that evolved long before multicellular
life existed on earth and seeded the galaxy with incomprehensible artefacts and
colossal engineering projects. Vim is like a lovable chainsaw-studded robot
with the most elegant keyboard interface in history secretly emblazoned on its
shining diamond heart.
It's worth the time it takes to learn one of the serious editors, but there are
easier places to start. Nano, for example, is easy to pick up, and should be
available on most systems. To start it, just say:
$ nano file
You should see something like this:
{nano.png}
Arrow keys will move your cursor around, and typing stuff will make it appear
in the file. This is pretty much like every other editor you've ever used. If
you haven't used Nano before, that stuff along the bottom of the terminal is a
reference to the most commonly used commands. `^` is a convention for "Ctrl",
so `^O` means Ctrl-o (the case of the letter doesn't actually matter), which
will save the file you're working on. Ctrl-x will quit, which is probably the
first important thing to know about any given editor.
scripting
---------
So back to putting commands in text files.
<!-- exec -->
$ cat lspoems
#!/bin/bash
# a script to find poems marked as good
find ~/p1k3/archives -name 'meta-ok-poem' | xargs dirname
<!-- end -->
<!-- exec -->
$ ./lspoems
/home/brennen/p1k3/archives/2013/2/9/meta-ok-poem
<!-- end -->

+ 2
- 1
render.pl View File

@ -59,7 +59,8 @@ sub handle_block {
sub replace_some_stuff {
my ($markup) = @_;
$markup =~ s{<code>(\$ .*?)$}{<code><b>$1</b>}gm;
# bold first "$ command" string in a code block
# $markup =~ s{<code>(\$ .*?)$}{<code><b>$1</b>}gm;
my @contents;


programs/markpoem → script/addmeta View File


+ 0
- 0
script/findmeta View File


+ 201
- 0
script/index.md View File

@ -0,0 +1,201 @@
4. script
=========
Back in chapter 1, I said that "the way you use the computer is often just to write
little programs that invoke other programs". In fact, we've already gone over a
bunch of these. Grepping through the text of a previous chapter should pull
up some good examples:
<!-- exec -->
$ grep -E '[a-z]+.*\| ' ../literary_environment/index.md
$ sort -k2 authors_* | uniq
$ sort colors | uniq -i -c
$ sort authors_* | uniq > all_authors
thing as `cat all_authors | nl`, or `nl all_authors`. You won't see this as
$ find ~/p1k3/archives/2010/11 -regextype egrep -regex '.*([0-9]+|index)' -type f | xargs wc -w | grep total
$ sort authors_* | uniq | wc -l
$ dict concatenate | head -10
$ sort colors | uniq -i | tail -1
$ cut -d' ' -f1 ./authors_* | sort | uniq -ci | sort -n | tail -3
$ sort -u ./authors_* | cut -d' ' -f1 | uniq -ci | sort -n | tail -3
$ cat ./authors_* | grep 'Vanessa'
<!-- end -->
None of these one-liners do all that much, but they all take input of one sort
or another and transform it into something new by doing a series of things to
it. They're little formal sentences describing how to make one thing into
another, which is as good a definition of programming as most. Or at least
this is a good way to describe programming-in-the-small. (A lot of the
programs we use day-to-day are more like essays, novels, or interminable
Fantasy series where every character you like dies horribly than they are like
individual sentences.)
One-liners like these are all well and good when you're staring at a terminal,
trying to figure something out - but what about when you've already figured it out and
you want to repeat it in the future?
It turns out that Bash has you covered. Since shell commands are just text,
they can live in a text file as easily as they can be typed.
learn you an editor
-------------------
We've skirted the topic so far, but now that we're talking about writing out
text files in earnest, you're going to want a text editor.
My editor is where I spend most of my time that isn't in a web browser, because
it's where I write both code and prose. It turns out that the features which
make a good code editor overlap a lot with the ones that make a good editor of
English sentences.
So what should you use? Well, there have been other contenders in recent
years, but in truth nothing comes close to dethroning the Great Old Ones of
text editing. Emacs is a creature both primal and sophisticated, like an
avatar of some interstellar civilization that evolved long before multicellular
life existed on earth and seeded the galaxy with incomprehensible artefacts and
colossal engineering projects. Vim is like a lovable chainsaw-studded robot
with the most elegant keyboard interface in history secretly emblazoned on its
shining diamond heart.
It's worth the time it takes to learn one of the serious editors, but there are
easier places to start. Nano, for example, is easy to pick up, and should be
available on most systems. To start it, just say:
$ nano file
You should see something like this:
{nano.png}
Arrow keys will move your cursor around, and typing stuff will make it appear
in the file. This is pretty much like every other editor you've ever used. If
you haven't used Nano before, that stuff along the bottom of the terminal is a
reference to the most commonly used commands. `^` is a convention for "Ctrl",
so `^O` means Ctrl-o (the case of the letter doesn't actually matter), which
will save the file you're working on. Ctrl-x will quit, which is probably the
first important thing to know about any given editor.
d.i.y. utilities
----------------
So back to putting commands in text files.
{much verbiage about scripts to come}
<!-- exec -->
$ cat okpoems
#!/bin/bash
# find all the marker files and get the name of
# the directory containing each
find ~/p1k3/archives -name 'meta-ok-poem' | xargs dirname
exit 0
<!-- end -->
<!-- exec -->
$ ./okpoems
/home/brennen/p1k3/archives/2013/2/9
/home/brennen/p1k3/archives/2012/3/17
/home/brennen/p1k3/archives/2012/3/26
<!-- end -->
<!-- exec -->
$ cat markpoem
#!/bin/bash
# $1 is the first parameter to our script
POEM=$1
# Complain and exit if we weren't given a path:
if [ ! $POEM ]
then
echo 'usage: markpoem <path>'
# Confusingly, an exit status of 0 means to the shell that everything went
# fine, while any other number means that something went wrong.
exit 64
fi
if [ ! -e $POEM ]
then
echo "$POEM not found"
exit 66
fi
echo "marking $1 an ok poem"
POEM_BASENAME=$(basename $POEM)
# If the target is a plain file instead of a directory, make it into
# a directory and move the content into $POEM/index:
if [ -f $POEM ]
then
echo "making $POEM into a directory, moving content to"
echo " $POEM/index"
TEMPFILE="/tmp/$POEM_BASENAME.$(date +%s.%N)"
mv $POEM $TEMPFILE
mkdir $POEM
mv $TEMPFILE $POEM/index
fi
if [ -d $POEM ]
then
# touch(1) will either create the file or update its timestamp:
touch $POEM/meta-ok-poem
else
echo "something broke - why isn't $POEM a directory?"
file $POEM
fi
# Signal that all is copacetic:
echo kthxbai
exit 0
<!-- end -->
These are imperfect, but they were quick to write, they're made out of standard
commands, and I don't yet hate myself for them. These are all signs that I'm
not totally on the wrong track with the `meta-ok-poem` abstraction, and could
build it into my ongoing writing project. These scripts would also be easy to
hook into with custom keybindings in my editor. With a few more lines of code,
I can build a system to wade through the list of candidate files one at a time
and mark the interesting ones.
a confession
------------
I kind of hate shell scripts, and I think it's ok if you hate them too.
That doesn't mean you shouldn't _know_ about them, or that you shouldn't
_write_ them. I write little tiny ones all the time, and the ability to read
other people's scripts comes in handy. Oftentimes, the best, most tasteful way
to automate something is to build a script out of the commonly available
commands. They're already there on millions of machines. Many of them have
been pretty well understood for a generation, and most of them will probably be
around for a generation or three to come. They do neat stuff. Scripts let you
build on the things you've already figured out on the command line, and give
repeatable operations a memorable, user-friendly name.
One of the reliable markers of powerful software is that it can be scripted: It
extends to its users some of the same power that its authors used in creating
it. Scriptable software is to some extent _living_ software. It's a book that
you, the reader, get to help write.
In all these ways, shell scripts are wonderful, and a little bit magical, and
actually, quietly indispensable to the machinery of modern civilization.
Unfortunately, in all the ways that a shell like Bash itself is ugly, finicky,
and covered in 40 years of weird, incidental cruft, long-form Bash scripts are
even worse. Bash is a useful glue language, particularly for things composed
in the flow of work on the command line. Syntactic and conceptual innovations
like pipes are beautiful and necessary. What Bash is _not_, despite its power,
is a very good general purpose programming language. It turns out those are
really nice to have at your disposal.

+ 49
- 0
script/markpoem View File

@ -0,0 +1,49 @@
#!/bin/bash
# $1 is the first parameter to our script
POEM=$1
# Complain and exit if we weren't given a path:
if [ ! $POEM ]
then
echo 'usage: markpoem <path>'
# Confusingly, an exit status of 0 means to the shell that everything went
# fine, while any other number means that something went wrong.
exit 64
fi
if [ ! -e $POEM ]
then
echo "$POEM not found"
exit 66
fi
echo "marking $1 an ok poem"
POEM_BASENAME=$(basename $POEM)
# If the target is a plain file instead of a directory, make it into
# a directory and move the content into $POEM/index:
if [ -f $POEM ]
then
echo "making $POEM into a directory, moving content to"
echo " $POEM/index"
TEMPFILE="/tmp/$POEM_BASENAME.$(date +%s.%N)"
mv $POEM $TEMPFILE
mkdir $POEM
mv $TEMPFILE $POEM/index
fi
if [ -d $POEM ]
then
# touch(1) will either create the file or update its timestamp:
touch $POEM/meta-ok-poem
else
echo "something broke - why isn't $POEM a directory?"
file $POEM
fi
# Signal that all is copacetic:
echo kthxbai
exit 0

programs/lspoems → script/okpoems View File

@ -3,3 +3,5 @@
# find all the marker files and get the name of
# the directory containing each
find ~/p1k3/archives -name 'meta-ok-poem' | xargs dirname
exit 0

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