improved indentation and whitespace for markdown code blocks
All code blocks in markdown have been intended by at least 4 spaces. We add `--tab-stop=8` to all `pandoc(1)` executions in order to set a better tab stop indentation, especially for tab intended code blocks. Changed `bin/pandoc-wrapper.sh` VERSION from "1.5.3 2024-03-26" to "1.6 2024-03-31". Fixed `1991/brnstnd/sorta.README.md` so that the sorta code is code blocks. Removed unneeded paragraph group in copyright in `inc/footer.default.html`. Fixed excess whitespace after list Author on entry `index.html` page. Changed `bin/output-index-author.sh` VERSION from "1.5.2 2024-03-26" to "1.6 2024-03-31". Performed `make www` to perform the above and test under macOS. TODO: Fix the problem of the initial line of code being extra intended. TODO: Fix excess whitespace around code that is inline.
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+27
-27
@@ -1,7 +1,7 @@
|
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## To build:
|
||||
|
||||
```sh
|
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make all
|
||||
make all
|
||||
```
|
||||
|
||||
The authors provided another version of this program. See the [alternate
|
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@@ -13,7 +13,7 @@ version](#alternate-code) section below.
|
||||
The current status of this entry is:
|
||||
|
||||
```
|
||||
STATUS: INABIAF - please **DO NOT** fix
|
||||
STATUS: INABIAF - please **DO NOT** fix
|
||||
```
|
||||
|
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For more detailed information see [1990 tbr bugs](../../bugs.html#1990_tbr).
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@@ -26,8 +26,8 @@ output due to a warning at runtime that was interspersed with the output of the
|
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program. For instance it would show:
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|
||||
```sh
|
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./tbr
|
||||
$ warning: this program uses gets(), which is unsafe.
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./tbr
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||||
$ warning: this program uses gets(), which is unsafe.
|
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```
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|
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which kind of hid the prompt. Thus the entry was changed to use `fgets(3)` which
|
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@@ -41,8 +41,8 @@ below, in the [alternate version](#alternate-code) section.
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## To use:
|
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|
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```sh
|
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./tbr
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$ enter some shell commands
|
||||
./tbr
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$ enter some shell commands
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```
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|
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NOTE: globs do not work with this entry. Why?
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@@ -55,16 +55,16 @@ just `exit` or `logout`? Hint: see the authors' remarks.
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## Try:
|
||||
|
||||
```sh
|
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./tbr
|
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$ ls -l tbr tbr.c
|
||||
./tbr
|
||||
$ ls -l tbr tbr.c
|
||||
|
||||
# notice how the following does not work:
|
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ls tbr*
|
||||
# notice how the following does not work:
|
||||
ls tbr*
|
||||
|
||||
# try figuring out how this entry works in an editor:
|
||||
vi tbr.c
|
||||
# try figuring out how this entry works in an editor:
|
||||
vi tbr.c
|
||||
|
||||
# then figure out how to exit vi :-)
|
||||
# then figure out how to exit vi :-)
|
||||
```
|
||||
|
||||
What happens if you try using `cd -` to return to previous directory? What about
|
||||
@@ -80,16 +80,16 @@ The authors supplied us with a slightly smaller unformatted version
|
||||
of the program which we include below:
|
||||
|
||||
```c
|
||||
#define D ,close(
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||||
char*c,q[512],m[256],*v[99],**u,*i[3];int f[2],p;main(){for(m[m[60]=m[62]=
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||||
32]=m[*m=124[m]=9]=6;e(-8),gets(1+(c=q))||(exit(0),0);r(0,0))for(;*++c;);}
|
||||
r(t,o){*i=i[2]=0;for(u=v+98;m[*--c]^9;m[*c]&32?i[*c&2]=
|
||||
*u,u-v^98&&++u:3)if(!m[*c]){for(*++c=0;!m[*--c];);*--u=
|
||||
++c;}u-v^98?strcmp(*u,"cd")?*c?pipe(f),o=f[1]:1,(p=fork())?e(p),o?
|
||||
r(o,0)D o)D*f):4,wait(0):(o?dup2(*f,0)D*f)D o):*i?1 D
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0),e(open(*i,0)):5,t?dup2(t,1)D t):i[2]?9 D
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||||
1),e(creat(i[2],438)):2,e(execvp(*u,u))):e(chdir(u[1])*2):6;}
|
||||
e(x){x<0?write(2,"?\n$ "-x/4,2),x+1||(exit(1),0):5;}
|
||||
#define D ,close(
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char*c,q[512],m[256],*v[99],**u,*i[3];int f[2],p;main(){for(m[m[60]=m[62]=
|
||||
32]=m[*m=124[m]=9]=6;e(-8),gets(1+(c=q))||(exit(0),0);r(0,0))for(;*++c;);}
|
||||
r(t,o){*i=i[2]=0;for(u=v+98;m[*--c]^9;m[*c]&32?i[*c&2]=
|
||||
*u,u-v^98&&++u:3)if(!m[*c]){for(*++c=0;!m[*--c];);*--u=
|
||||
++c;}u-v^98?strcmp(*u,"cd")?*c?pipe(f),o=f[1]:1,(p=fork())?e(p),o?
|
||||
r(o,0)D o)D*f):4,wait(0):(o?dup2(*f,0)D*f)D o):*i?1 D
|
||||
0),e(open(*i,0)):5,t?dup2(t,1)D t):i[2]?9 D
|
||||
1),e(creat(i[2],438)):2,e(execvp(*u,u))):e(chdir(u[1])*2):6;}
|
||||
e(x){x<0?write(2,"?\n$ "-x/4,2),x+1||(exit(1),0):5;}
|
||||
```
|
||||
|
||||
and in the [alternate source](tbr.alt.c). It has the `exit()` returns `void` fix
|
||||
@@ -100,14 +100,14 @@ equivalent like the authors intended.
|
||||
### Alternate build:
|
||||
|
||||
```sh
|
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make alt
|
||||
make alt
|
||||
```
|
||||
|
||||
|
||||
### Alternate use:
|
||||
|
||||
```sh
|
||||
./tbr.alt
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./tbr.alt
|
||||
```
|
||||
|
||||
|
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@@ -166,13 +166,13 @@ shell flags an error if no arguments are on the stack. Thus, for
|
||||
example:
|
||||
|
||||
```sh
|
||||
cat > foo > bar
|
||||
cat > foo > bar
|
||||
```
|
||||
|
||||
cats to `foo`, since it was pushed last, but
|
||||
|
||||
```sh
|
||||
cat > > foo bar
|
||||
cat > > foo bar
|
||||
```
|
||||
|
||||
cats to `bar`, since `bar` was pushed under `foo` (remember we're
|
||||
|
||||
+28
-29
@@ -135,8 +135,7 @@
|
||||
Location: <a href="../../location.html#US">US</a> - <em>United States of America</em> (<em>United States</em>)
|
||||
<br><br></li>
|
||||
<li>Name: <a href="../../authors.html#Sean_Dorward">Sean Dorward</a><br>
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||||
Location: <a href="../../location.html#ZZ">ZZ</a> - <em>Unknown location</em>
|
||||
<br><br></li>
|
||||
Location: <a href="../../location.html#ZZ">ZZ</a> - <em>Unknown location</em></li>
|
||||
</ul>
|
||||
|
||||
<!-- END: next line ends content generated by: bin/output-index-author.sh -->
|
||||
@@ -145,42 +144,42 @@ Location: <a href="../../location.html#ZZ">ZZ</a> - <em>Unknown location</em>
|
||||
<!-- START: this line starts content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
|
||||
|
||||
<h2 id="to-build">To build:</h2>
|
||||
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="fu">make</span> all</span></code></pre></div>
|
||||
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a> <span class="fu">make</span> all</span></code></pre></div>
|
||||
<p>The authors provided another version of this program. See the <a href="#alternate-code">alternate
|
||||
version</a> section below.</p>
|
||||
<h3 id="bugs-and-misfeatures">Bugs and (Mis)features:</h3>
|
||||
<p>The current status of this entry is:</p>
|
||||
<pre><code>STATUS: INABIAF - please **DO NOT** fix</code></pre>
|
||||
<pre><code> STATUS: INABIAF - please **DO NOT** fix</code></pre>
|
||||
<p>For more detailed information see <a href="../../bugs.html#1990_tbr">1990 tbr bugs</a>.</p>
|
||||
<h3 id="a-note-about-the-fixes-of-this-entry-in-2023">A note about the fixes of this entry in 2023:</h3>
|
||||
<p>In 2023 it was noticed that in some systems like macOS there was confusing
|
||||
output due to a warning at runtime that was interspersed with the output of the
|
||||
program. For instance it would show:</p>
|
||||
<div class="sourceCode" id="cb3"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb3-1"><a href="#cb3-1" aria-hidden="true" tabindex="-1"></a><span class="ex">./tbr</span></span>
|
||||
<span id="cb3-2"><a href="#cb3-2" aria-hidden="true" tabindex="-1"></a><span class="ex">$</span> warning: this program uses gets<span class="er">(</span><span class="kw">)</span><span class="ex">,</span> which is unsafe.</span></code></pre></div>
|
||||
<div class="sourceCode" id="cb3"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb3-1"><a href="#cb3-1" aria-hidden="true" tabindex="-1"></a> <span class="ex">./tbr</span></span>
|
||||
<span id="cb3-2"><a href="#cb3-2" aria-hidden="true" tabindex="-1"></a> <span class="ex">$</span> warning: this program uses gets<span class="er">(</span><span class="kw">)</span><span class="ex">,</span> which is unsafe.</span></code></pre></div>
|
||||
<p>which kind of hid the prompt. Thus the entry was changed to use <code>fgets(3)</code> which
|
||||
is referred to later in this file.</p>
|
||||
<p>Also <code>exit(3)</code> returns <code>void</code> but the entry was using it in a binary expression so
|
||||
this entry would not compile in modern systems. This fix is also referred to
|
||||
below, in the <a href="#alternate-code">alternate version</a> section.</p>
|
||||
<h2 id="to-use">To use:</h2>
|
||||
<div class="sourceCode" id="cb4"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb4-1"><a href="#cb4-1" aria-hidden="true" tabindex="-1"></a><span class="ex">./tbr</span></span>
|
||||
<span id="cb4-2"><a href="#cb4-2" aria-hidden="true" tabindex="-1"></a><span class="ex">$</span> enter some shell commands</span></code></pre></div>
|
||||
<div class="sourceCode" id="cb4"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb4-1"><a href="#cb4-1" aria-hidden="true" tabindex="-1"></a> <span class="ex">./tbr</span></span>
|
||||
<span id="cb4-2"><a href="#cb4-2" aria-hidden="true" tabindex="-1"></a> <span class="ex">$</span> enter some shell commands</span></code></pre></div>
|
||||
<p>NOTE: globs do not work with this entry. Why?</p>
|
||||
<p>NOTE: <code>exit</code> does not work and neither does <code>logout</code>. To exit try sending ctrl-d
|
||||
or ctrl-c (or kill it from another terminal :-) ). But why does it not work with
|
||||
just <code>exit</code> or <code>logout</code>? Hint: see the authors’ remarks.</p>
|
||||
<h2 id="try">Try:</h2>
|
||||
<div class="sourceCode" id="cb5"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb5-1"><a href="#cb5-1" aria-hidden="true" tabindex="-1"></a><span class="ex">./tbr</span></span>
|
||||
<span id="cb5-2"><a href="#cb5-2" aria-hidden="true" tabindex="-1"></a><span class="ex">$</span> ls <span class="at">-l</span> tbr tbr.c</span>
|
||||
<div class="sourceCode" id="cb5"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb5-1"><a href="#cb5-1" aria-hidden="true" tabindex="-1"></a> <span class="ex">./tbr</span></span>
|
||||
<span id="cb5-2"><a href="#cb5-2" aria-hidden="true" tabindex="-1"></a> <span class="ex">$</span> ls <span class="at">-l</span> tbr tbr.c</span>
|
||||
<span id="cb5-3"><a href="#cb5-3" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb5-4"><a href="#cb5-4" aria-hidden="true" tabindex="-1"></a><span class="co"># notice how the following does not work:</span></span>
|
||||
<span id="cb5-5"><a href="#cb5-5" aria-hidden="true" tabindex="-1"></a><span class="fu">ls</span> tbr<span class="pp">*</span></span>
|
||||
<span id="cb5-4"><a href="#cb5-4" aria-hidden="true" tabindex="-1"></a> <span class="co"># notice how the following does not work:</span></span>
|
||||
<span id="cb5-5"><a href="#cb5-5" aria-hidden="true" tabindex="-1"></a> <span class="fu">ls</span> tbr<span class="pp">*</span></span>
|
||||
<span id="cb5-6"><a href="#cb5-6" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb5-7"><a href="#cb5-7" aria-hidden="true" tabindex="-1"></a><span class="co"># try figuring out how this entry works in an editor:</span></span>
|
||||
<span id="cb5-8"><a href="#cb5-8" aria-hidden="true" tabindex="-1"></a><span class="fu">vi</span> tbr.c</span>
|
||||
<span id="cb5-7"><a href="#cb5-7" aria-hidden="true" tabindex="-1"></a> <span class="co"># try figuring out how this entry works in an editor:</span></span>
|
||||
<span id="cb5-8"><a href="#cb5-8" aria-hidden="true" tabindex="-1"></a> <span class="fu">vi</span> tbr.c</span>
|
||||
<span id="cb5-9"><a href="#cb5-9" aria-hidden="true" tabindex="-1"></a></span>
|
||||
<span id="cb5-10"><a href="#cb5-10" aria-hidden="true" tabindex="-1"></a><span class="co"># then figure out how to exit vi :-)</span></span></code></pre></div>
|
||||
<span id="cb5-10"><a href="#cb5-10" aria-hidden="true" tabindex="-1"></a> <span class="co"># then figure out how to exit vi :-)</span></span></code></pre></div>
|
||||
<p>What happens if you try using <code>cd -</code> to return to previous directory? What about
|
||||
<code>cd</code> with no args?</p>
|
||||
<p>The authors include a section called <a href="#bugs">BUGS</a> that, because they were
|
||||
@@ -188,23 +187,23 @@ documented, are not considered bugs as such in the context of the contest.</p>
|
||||
<h2 id="alternate-code">Alternate code:</h2>
|
||||
<p>The authors supplied us with a slightly smaller unformatted version
|
||||
of the program which we include below:</p>
|
||||
<div class="sourceCode" id="cb6"><pre class="sourceCode c"><code class="sourceCode c"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a><span class="pp">#define D </span><span class="op">,</span><span class="pp">close</span><span class="op">(</span></span>
|
||||
<span id="cb6-2"><a href="#cb6-2" aria-hidden="true" tabindex="-1"></a><span class="dt">char</span><span class="op">*</span>c<span class="op">,</span>q<span class="op">[</span><span class="dv">512</span><span class="op">],</span>m<span class="op">[</span><span class="dv">256</span><span class="op">],*</span>v<span class="op">[</span><span class="dv">99</span><span class="op">],**</span>u<span class="op">,*</span>i<span class="op">[</span><span class="dv">3</span><span class="op">];</span><span class="dt">int</span> f<span class="op">[</span><span class="dv">2</span><span class="op">],</span>p<span class="op">;</span>main<span class="op">(){</span><span class="cf">for</span><span class="op">(</span>m<span class="op">[</span>m<span class="op">[</span><span class="dv">60</span><span class="op">]=</span>m<span class="op">[</span><span class="dv">62</span><span class="op">]=</span></span>
|
||||
<span id="cb6-3"><a href="#cb6-3" aria-hidden="true" tabindex="-1"></a><span class="dv">32</span><span class="op">]=</span>m<span class="op">[*</span>m<span class="op">=</span><span class="dv">124</span><span class="op">[</span>m<span class="op">]=</span><span class="dv">9</span><span class="op">]=</span><span class="dv">6</span><span class="op">;</span>e<span class="op">(-</span><span class="dv">8</span><span class="op">),</span>gets<span class="op">(</span><span class="dv">1</span><span class="op">+(</span>c<span class="op">=</span>q<span class="op">))||(</span>exit<span class="op">(</span><span class="dv">0</span><span class="op">),</span><span class="dv">0</span><span class="op">);</span>r<span class="op">(</span><span class="dv">0</span><span class="op">,</span><span class="dv">0</span><span class="op">))</span><span class="cf">for</span><span class="op">(;*++</span>c<span class="op">;);}</span></span>
|
||||
<span id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a>r<span class="op">(</span>t<span class="op">,</span>o<span class="op">){*</span>i<span class="op">=</span>i<span class="op">[</span><span class="dv">2</span><span class="op">]=</span><span class="dv">0</span><span class="op">;</span><span class="cf">for</span><span class="op">(</span>u<span class="op">=</span>v<span class="op">+</span><span class="dv">98</span><span class="op">;</span>m<span class="op">[*--</span>c<span class="op">]^</span><span class="dv">9</span><span class="op">;</span>m<span class="op">[*</span>c<span class="op">]&</span><span class="dv">32</span><span class="op">?</span>i<span class="op">[*</span>c<span class="op">&</span><span class="dv">2</span><span class="op">]=</span></span>
|
||||
<span id="cb6-5"><a href="#cb6-5" aria-hidden="true" tabindex="-1"></a><span class="op">*</span>u<span class="op">,</span>u<span class="op">-</span>v<span class="op">^</span><span class="dv">98</span><span class="op">&&++</span>u<span class="op">:</span><span class="dv">3</span><span class="op">)</span><span class="cf">if</span><span class="op">(!</span>m<span class="op">[*</span>c<span class="op">]){</span><span class="cf">for</span><span class="op">(*++</span>c<span class="op">=</span><span class="dv">0</span><span class="op">;!</span>m<span class="op">[*--</span>c<span class="op">];);*--</span>u<span class="op">=</span></span>
|
||||
<span id="cb6-6"><a href="#cb6-6" aria-hidden="true" tabindex="-1"></a><span class="op">++</span>c<span class="op">;}</span>u<span class="op">-</span>v<span class="op">^</span><span class="dv">98</span><span class="op">?</span>strcmp<span class="op">(*</span>u<span class="op">,</span><span class="st">"cd"</span><span class="op">)?*</span>c<span class="op">?</span>pipe<span class="op">(</span>f<span class="op">),</span>o<span class="op">=</span>f<span class="op">[</span><span class="dv">1</span><span class="op">]:</span><span class="dv">1</span><span class="op">,(</span>p<span class="op">=</span>fork<span class="op">())?</span>e<span class="op">(</span>p<span class="op">),</span>o<span class="op">?</span></span>
|
||||
<span id="cb6-7"><a href="#cb6-7" aria-hidden="true" tabindex="-1"></a>r<span class="op">(</span>o<span class="op">,</span><span class="dv">0</span><span class="op">)</span>D o<span class="op">)</span>D<span class="op">*</span>f<span class="op">):</span><span class="dv">4</span><span class="op">,</span>wait<span class="op">(</span><span class="dv">0</span><span class="op">):(</span>o<span class="op">?</span>dup2<span class="op">(*</span>f<span class="op">,</span><span class="dv">0</span><span class="op">)</span>D<span class="op">*</span>f<span class="op">)</span>D o<span class="op">):*</span>i<span class="op">?</span><span class="dv">1</span> D</span>
|
||||
<span id="cb6-8"><a href="#cb6-8" aria-hidden="true" tabindex="-1"></a><span class="dv">0</span><span class="op">),</span>e<span class="op">(</span>open<span class="op">(*</span>i<span class="op">,</span><span class="dv">0</span><span class="op">)):</span><span class="dv">5</span><span class="op">,</span>t<span class="op">?</span>dup2<span class="op">(</span>t<span class="op">,</span><span class="dv">1</span><span class="op">)</span>D t<span class="op">):</span>i<span class="op">[</span><span class="dv">2</span><span class="op">]?</span><span class="dv">9</span> D</span>
|
||||
<span id="cb6-9"><a href="#cb6-9" aria-hidden="true" tabindex="-1"></a><span class="dv">1</span><span class="op">),</span>e<span class="op">(</span>creat<span class="op">(</span>i<span class="op">[</span><span class="dv">2</span><span class="op">],</span><span class="dv">438</span><span class="op">)):</span><span class="dv">2</span><span class="op">,</span>e<span class="op">(</span>execvp<span class="op">(*</span>u<span class="op">,</span>u<span class="op">))):</span>e<span class="op">(</span>chdir<span class="op">(</span>u<span class="op">[</span><span class="dv">1</span><span class="op">])*</span><span class="dv">2</span><span class="op">):</span><span class="dv">6</span><span class="op">;}</span></span>
|
||||
<span id="cb6-10"><a href="#cb6-10" aria-hidden="true" tabindex="-1"></a>e<span class="op">(</span>x<span class="op">){</span>x<span class="op"><</span><span class="dv">0</span><span class="op">?</span>write<span class="op">(</span><span class="dv">2</span><span class="op">,</span><span class="st">"?</span><span class="sc">\n</span><span class="st">$ "</span><span class="op">-</span>x<span class="op">/</span><span class="dv">4</span><span class="op">,</span><span class="dv">2</span><span class="op">),</span>x<span class="op">+</span><span class="dv">1</span><span class="op">||(</span>exit<span class="op">(</span><span class="dv">1</span><span class="op">),</span><span class="dv">0</span><span class="op">):</span><span class="dv">5</span><span class="op">;}</span></span></code></pre></div>
|
||||
<div class="sourceCode" id="cb6"><pre class="sourceCode c"><code class="sourceCode c"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a> <span class="pp">#define D </span><span class="op">,</span><span class="pp">close</span><span class="op">(</span></span>
|
||||
<span id="cb6-2"><a href="#cb6-2" aria-hidden="true" tabindex="-1"></a> <span class="dt">char</span><span class="op">*</span>c<span class="op">,</span>q<span class="op">[</span><span class="dv">512</span><span class="op">],</span>m<span class="op">[</span><span class="dv">256</span><span class="op">],*</span>v<span class="op">[</span><span class="dv">99</span><span class="op">],**</span>u<span class="op">,*</span>i<span class="op">[</span><span class="dv">3</span><span class="op">];</span><span class="dt">int</span> f<span class="op">[</span><span class="dv">2</span><span class="op">],</span>p<span class="op">;</span>main<span class="op">(){</span><span class="cf">for</span><span class="op">(</span>m<span class="op">[</span>m<span class="op">[</span><span class="dv">60</span><span class="op">]=</span>m<span class="op">[</span><span class="dv">62</span><span class="op">]=</span></span>
|
||||
<span id="cb6-3"><a href="#cb6-3" aria-hidden="true" tabindex="-1"></a> <span class="dv">32</span><span class="op">]=</span>m<span class="op">[*</span>m<span class="op">=</span><span class="dv">124</span><span class="op">[</span>m<span class="op">]=</span><span class="dv">9</span><span class="op">]=</span><span class="dv">6</span><span class="op">;</span>e<span class="op">(-</span><span class="dv">8</span><span class="op">),</span>gets<span class="op">(</span><span class="dv">1</span><span class="op">+(</span>c<span class="op">=</span>q<span class="op">))||(</span>exit<span class="op">(</span><span class="dv">0</span><span class="op">),</span><span class="dv">0</span><span class="op">);</span>r<span class="op">(</span><span class="dv">0</span><span class="op">,</span><span class="dv">0</span><span class="op">))</span><span class="cf">for</span><span class="op">(;*++</span>c<span class="op">;);}</span></span>
|
||||
<span id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a> r<span class="op">(</span>t<span class="op">,</span>o<span class="op">){*</span>i<span class="op">=</span>i<span class="op">[</span><span class="dv">2</span><span class="op">]=</span><span class="dv">0</span><span class="op">;</span><span class="cf">for</span><span class="op">(</span>u<span class="op">=</span>v<span class="op">+</span><span class="dv">98</span><span class="op">;</span>m<span class="op">[*--</span>c<span class="op">]^</span><span class="dv">9</span><span class="op">;</span>m<span class="op">[*</span>c<span class="op">]&</span><span class="dv">32</span><span class="op">?</span>i<span class="op">[*</span>c<span class="op">&</span><span class="dv">2</span><span class="op">]=</span></span>
|
||||
<span id="cb6-5"><a href="#cb6-5" aria-hidden="true" tabindex="-1"></a> <span class="op">*</span>u<span class="op">,</span>u<span class="op">-</span>v<span class="op">^</span><span class="dv">98</span><span class="op">&&++</span>u<span class="op">:</span><span class="dv">3</span><span class="op">)</span><span class="cf">if</span><span class="op">(!</span>m<span class="op">[*</span>c<span class="op">]){</span><span class="cf">for</span><span class="op">(*++</span>c<span class="op">=</span><span class="dv">0</span><span class="op">;!</span>m<span class="op">[*--</span>c<span class="op">];);*--</span>u<span class="op">=</span></span>
|
||||
<span id="cb6-6"><a href="#cb6-6" aria-hidden="true" tabindex="-1"></a> <span class="op">++</span>c<span class="op">;}</span>u<span class="op">-</span>v<span class="op">^</span><span class="dv">98</span><span class="op">?</span>strcmp<span class="op">(*</span>u<span class="op">,</span><span class="st">"cd"</span><span class="op">)?*</span>c<span class="op">?</span>pipe<span class="op">(</span>f<span class="op">),</span>o<span class="op">=</span>f<span class="op">[</span><span class="dv">1</span><span class="op">]:</span><span class="dv">1</span><span class="op">,(</span>p<span class="op">=</span>fork<span class="op">())?</span>e<span class="op">(</span>p<span class="op">),</span>o<span class="op">?</span></span>
|
||||
<span id="cb6-7"><a href="#cb6-7" aria-hidden="true" tabindex="-1"></a> r<span class="op">(</span>o<span class="op">,</span><span class="dv">0</span><span class="op">)</span>D o<span class="op">)</span>D<span class="op">*</span>f<span class="op">):</span><span class="dv">4</span><span class="op">,</span>wait<span class="op">(</span><span class="dv">0</span><span class="op">):(</span>o<span class="op">?</span>dup2<span class="op">(*</span>f<span class="op">,</span><span class="dv">0</span><span class="op">)</span>D<span class="op">*</span>f<span class="op">)</span>D o<span class="op">):*</span>i<span class="op">?</span><span class="dv">1</span> D</span>
|
||||
<span id="cb6-8"><a href="#cb6-8" aria-hidden="true" tabindex="-1"></a> <span class="dv">0</span><span class="op">),</span>e<span class="op">(</span>open<span class="op">(*</span>i<span class="op">,</span><span class="dv">0</span><span class="op">)):</span><span class="dv">5</span><span class="op">,</span>t<span class="op">?</span>dup2<span class="op">(</span>t<span class="op">,</span><span class="dv">1</span><span class="op">)</span>D t<span class="op">):</span>i<span class="op">[</span><span class="dv">2</span><span class="op">]?</span><span class="dv">9</span> D</span>
|
||||
<span id="cb6-9"><a href="#cb6-9" aria-hidden="true" tabindex="-1"></a> <span class="dv">1</span><span class="op">),</span>e<span class="op">(</span>creat<span class="op">(</span>i<span class="op">[</span><span class="dv">2</span><span class="op">],</span><span class="dv">438</span><span class="op">)):</span><span class="dv">2</span><span class="op">,</span>e<span class="op">(</span>execvp<span class="op">(*</span>u<span class="op">,</span>u<span class="op">))):</span>e<span class="op">(</span>chdir<span class="op">(</span>u<span class="op">[</span><span class="dv">1</span><span class="op">])*</span><span class="dv">2</span><span class="op">):</span><span class="dv">6</span><span class="op">;}</span></span>
|
||||
<span id="cb6-10"><a href="#cb6-10" aria-hidden="true" tabindex="-1"></a> e<span class="op">(</span>x<span class="op">){</span>x<span class="op"><</span><span class="dv">0</span><span class="op">?</span>write<span class="op">(</span><span class="dv">2</span><span class="op">,</span><span class="st">"?</span><span class="sc">\n</span><span class="st">$ "</span><span class="op">-</span>x<span class="op">/</span><span class="dv">4</span><span class="op">,</span><span class="dv">2</span><span class="op">),</span>x<span class="op">+</span><span class="dv">1</span><span class="op">||(</span>exit<span class="op">(</span><span class="dv">1</span><span class="op">),</span><span class="dv">0</span><span class="op">):</span><span class="dv">5</span><span class="op">;}</span></span></code></pre></div>
|
||||
<p>and in the <a href="tbr.alt.c">alternate source</a>. It has the <code>exit()</code> returns <code>void</code> fix
|
||||
as well as the <code>gets()</code> to <code>fgets()</code> fix applied to it to make it functionally
|
||||
equivalent like the authors intended.</p>
|
||||
<h3 id="alternate-build">Alternate build:</h3>
|
||||
<div class="sourceCode" id="cb7"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb7-1"><a href="#cb7-1" aria-hidden="true" tabindex="-1"></a><span class="fu">make</span> alt</span></code></pre></div>
|
||||
<div class="sourceCode" id="cb7"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb7-1"><a href="#cb7-1" aria-hidden="true" tabindex="-1"></a> <span class="fu">make</span> alt</span></code></pre></div>
|
||||
<h3 id="alternate-use">Alternate use:</h3>
|
||||
<div class="sourceCode" id="cb8"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb8-1"><a href="#cb8-1" aria-hidden="true" tabindex="-1"></a><span class="ex">./tbr.alt</span></span></code></pre></div>
|
||||
<div class="sourceCode" id="cb8"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb8-1"><a href="#cb8-1" aria-hidden="true" tabindex="-1"></a> <span class="ex">./tbr.alt</span></span></code></pre></div>
|
||||
<h2 id="judges-remarks">Judges’ remarks:</h2>
|
||||
<p>This program touches on a well known Unix utility, the 6th edition Bourne Shell
|
||||
(<code>/bin/sh</code>), whose original source was considered to be extremely obfuscated by
|
||||
@@ -246,9 +245,9 @@ is parsed; a pointer to the stack of arguments is assigned and an
|
||||
argument is stolen every time a <code>></code> or <code><</code> is encountered. The
|
||||
shell flags an error if no arguments are on the stack. Thus, for
|
||||
example:</p>
|
||||
<div class="sourceCode" id="cb9"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb9-1"><a href="#cb9-1" aria-hidden="true" tabindex="-1"></a><span class="fu">cat</span> <span class="op">></span> foo <span class="op">></span> bar</span></code></pre></div>
|
||||
<div class="sourceCode" id="cb9"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb9-1"><a href="#cb9-1" aria-hidden="true" tabindex="-1"></a> <span class="fu">cat</span> <span class="op">></span> foo <span class="op">></span> bar</span></code></pre></div>
|
||||
<p>cats to <code>foo</code>, since it was pushed last, but</p>
|
||||
<div class="sourceCode" id="cb10"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb10-1"><a href="#cb10-1" aria-hidden="true" tabindex="-1"></a><span class="fu">cat</span> <span class="op">></span> <span class="op">></span> foo bar</span></code></pre></div>
|
||||
<div class="sourceCode" id="cb10"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb10-1"><a href="#cb10-1" aria-hidden="true" tabindex="-1"></a> <span class="fu">cat</span> <span class="op">></span> <span class="op">></span> foo bar</span></code></pre></div>
|
||||
<p>cats to <code>bar</code>, since <code>bar</code> was pushed under <code>foo</code> (remember we’re
|
||||
parsing right-left).</p>
|
||||
<p>Depending on your flavor of Unix, <code>cd</code> without an argument will
|
||||
|
||||
Reference in new issue
Block a user