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| author | garhve <git@garhve.com> | 2023-02-14 18:29:13 +0800 |
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| committer | garhve <git@garhve.com> | 2023-02-14 18:29:13 +0800 |
| commit | 734f042c9d99e0110d5e4cf8f2994a5ce27385d1 (patch) | |
| tree | 4b825dc642cb6eb9a060e54bf8d69288fbee4904 /public/post/mess-with-bash-1/index.html | |
| parent | 92e08c404fa53f304dec7490c4acb4b45dd0d7df (diff) | |
delete zola
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diff --git a/public/post/mess-with-bash-1/index.html b/public/post/mess-with-bash-1/index.html deleted file mode 100644 index 9d88957..0000000 --- a/public/post/mess-with-bash-1/index.html +++ /dev/null @@ -1,194 +0,0 @@ -<!DOCTYPE html> -<html lang="en"> - -<head> - <meta charset="utf-8"> - -<title>Mess with bash(1) | garhve's gibberish</title> - - - <link rel="shortcut icon" type="image/png" href="/images/favicon.png"> - <meta name="viewport" content="width=device-width,initial-scale=1"> - - <link id="stylesheet" rel="stylesheet" type="text/css" href="/dark.css"> - - <script type="text/javascript" src="/js/theme.js"></script> - -</head> - -<div class="header"> - <div class="site_title"> - <p><a href="/"><img src="https://blog.garhve.com/images/logo.png" alt="garhve's gibberish" - width="70" height=auto></a></p> - <p><a href="/"> garhve's gibberish</a></p> - </div> - <div class="menu"> - <!-- <a href="/tags">tags</a> - --><a href="/categories">categories</a> - </div> -</div> - -<body onload="getTheme()"> - <section class="section"> - <div class="container"> - -<p> - <div class="title_postpage">Mess with bash(1)</div> -</p> -<p> - <div class="date_postpage">2022-08-25</div> - <div class="taxonomies_postpage"> - - - <a href="https://blog.garhve.com/categories/code/">/code</a> - - - - -  <a href="https://blog.garhve.com/tags/bash/">#bash</a> - - - </div> -</p> - -<p> - <h3 id="crontab">Crontab</h3> -<p><code>crontab</code> is a useful tool, I really regret that I don't familar it earlier.</p> -<p>It's usage really simple, and these two are my frequent using:</p> -<pre data-lang="bash" style="background-color:#2e3440;color:#d8dee9;" class="language-bash "><code class="language-bash" data-lang="bash"><span style="color:#88c0d0;">crontab</span><span> -e </span><span style="color:#616e88;">#edit crontab file that reside in /var/spool/cron -</span><span style="color:#88c0d0;">crontab</span><span> -l </span><span style="color:#616e88;">#list current crontab job -</span></code></pre> -<p>It basic syntax as follow, also really simple -<img src="https://assets.garhve.com/pictures/screenshots/2022/08/1857817000.jpg" alt="crontab-layout.jpg" /></p> -<p>example of usage:</p> -<ol> -<li>delete file <em>foo</em> every minute -<code>* * * * * rm foo</code></li> -<li>delete file <em>foo</em> every 15 minutes -<code>15 * * * * rm foo</code></li> -<li>delete file <em>foo</em> every beginning of hour -<code>0 * * * * rm foo</code></li> -<li>delete file <em>foo</em> every minute after 3 hours -<code>* 3 * * * rm foo</code></li> -<li>delete file <em>foo</em> every day at 18:30 -<code>30 18 * * * rm foo</code></li> -<li>delete file <em>foo</em> every beginning of month -<code>0 0 0 * * rm foo</code></li> -<li>delete file <em>foo</em> on beginning of 1st,10th of month -<code>0 0 1,10 * * rm foo</code></li> -</ol> -<p>The usage really simple, I now use it to renew my SSL certification and daily update bt-tracker.</p> -<hr /> -<h3 id="tr">tr</h3> -<p><code>tr</code> is really useful when encountered situation that needs struggle with string. -Three frequency ways of using <code>tr</code></p> -<ol> -<li> -<p><strong>shrink</strong> multiple characters into single one</p> -<p><code>tr -s '[string]'</code> -e.g. <code>echo "ssssssspaaaaace" | tr -s 'sa'</code> would convert "ssssssspace" to "space"</p> -</li> -<li> -<p><strong>delete</strong> specific character. I usually use it to delete white space or delimiter</p> -<p><code>tr -d '[string]'</code> -e.g. <code>echo "blog.garhve.com" | tr -d '.o'</code> would convert url to "blggarhvecm"</p> -</li> -<li> -<p><strong>convert</strong> specific character to another one.</p> -<p><code>tr '[string1]' '[string2]'</code> -e.g. <code>echo "woopwon | tr "wo" "fe"</code> would result "feepfen"</p> -</li> -</ol> -<hr /> -<h3 id="cut">cut</h3> -<p>I use <code>cut</code> mostly to get word from a string, especially get relative path from absolute path. Because I always want to loop to get same sub-directories file from different main directory, <code>cut</code> helps a lot.</p> -<p>for now, I only use it one way</p> -<p><code>echo string | cut -d '[character]' -f position</code> -e.g. <code>echo path/to/most/inner/file | cut -d '/' -f1</code> this will give me word before first '/', which is 'path'</p> -<p>Often, <code>rev</code> will co-work with <code>cut</code> to get last one word</p> -<p>e.g. <code>echo blog.garhve.com | rev | cut -d '.' -f 1 | rev</code> this will give word after last '/', which is com.</p> -<blockquote> -<p><em>a worth noting here is that the <code>rev</code> command needs to appear twice because it usage is not so intuitive, it reverse whole string</em></p> -<p><code>echo "hello world" | rev</code> will get 'dlrow olleh`</p> -<p><code>echo "hello world" | cut -d ' ' -f1 | rev</code> will give result of 'dlrow'</p> -<p><code>echo "hello world" | rev | cut -d ' ' -f1</code> will give same result, as 'dlrow'</p> -<p><code>echo "hello world" | rev | cut -d ' ' -f1 | rev</code> will give expected result, as 'world'</p> -</blockquote> -<h3 id="daily-update-bt-tracker">Daily update bt tracker</h3> -<p>I already learn shell script for a while.. so I wrote a simple script to test whether I really got used to it, but result is obviously, I need more and more practice to memorize commands.</p> -<pre data-lang="bash" style="background-color:#2e3440;color:#d8dee9;" class="language-bash "><code class="language-bash" data-lang="bash"><span style="color:#616e88;">#! /bin/sh -</span><span style="color:#616e88;">#bt-tracker.txt -</span><span>site</span><span style="color:#81a1c1;">=</span><span style="color:#a3be8c;">https://raw.githubusercontent.com/ngosang/trackerslist/master/trackers_all.txt -</span><span> -</span><span>file</span><span style="color:#81a1c1;">=</span><span style="color:#a3be8c;">/path_to_aria_directory/aria2.conf -</span><span> -</span><span>Addr</span><span style="color:#81a1c1;">=</span><span style="color:#a3be8c;">user@addr -</span><span> -</span><span style="color:#616e88;"># Get bt-tracker and format it to fulfill aria needs, then store in variable -</span><span>bt</span><span style="color:#81a1c1;">=$</span><span style="color:#a3be8c;">(</span><span style="color:#88c0d0;">curl </span><span style="color:#81a1c1;">$</span><span>site </span><span style="color:#81a1c1;">| </span><span style="color:#88c0d0;">tr</span><span> -s </span><span style="color:#a3be8c;">'[:space:]' </span><span style="color:#81a1c1;">| </span><span style="color:#88c0d0;">tr </span><span style="color:#a3be8c;">'[:space:]' ',') -</span><span> -</span><span style="color:#616e88;"># sshpass is a software, that can allow me pass ssh password as argument -</span><span style="color:#616e88;"># so that I don't need to wait prompt -</span><span style="color:#616e88;"># 410 is the line of bt tracker resides, I now no other way to replace it. -</span><span style="color:#81a1c1;">$</span><span style="color:#88c0d0;">(sshpass</span><span> -p </span><span style="color:#a3be8c;">'password'</span><span style="color:#88c0d0;"> ssh</span><span> -T </span><span style="color:#81a1c1;">$</span><span>Addr </span><span style="color:#a3be8c;">"sed -i '410d' </span><span style="color:#81a1c1;">$</span><span>file</span><span style="color:#a3be8c;"> | echo </span><span style="color:#81a1c1;">$</span><span>bt</span><span style="color:#a3be8c;"> >> </span><span style="color:#81a1c1;">$</span><span>file</span><span style="color:#a3be8c;">"</span><span style="color:#88c0d0;">) -</span></code></pre> -<blockquote> -<p>Usage of <a href="https://blog.garhve.com/index.php/archives/23/#tr">tr</a> and <a href="https://blog.garhve.com/index.php/archives/23/#cut">cut</a>, expansion of 'command tips' is needed</p> -</blockquote> -<h3 id="ways-to-find-files-or-specific-string-in-files">Ways to find files or specific string in files</h3> -<p>In order to look up C definitions, I need to know where linux stores header files or which files store definitions I need. So that here comes up some methods to fulfill this need:</p> -<ol> -<li><code>find 'path' -name 'file_name'</code></li> -</ol> -<blockquote> -<p>e.g. <code>find / -name stdio.h</code> will return multiple location that stdio.h resides. this could expand to look for others</p> -<p><img src="https://assets.garhve.com/pictures/screenshots/2022/09/find_name.png" alt="image.png" /></p> -<p>more info could see <code>man find</code></p> -</blockquote> -<hr /> -<ol start="2"> -<li><code>grep -rnw 'path' -e 'pattern'</code></li> -</ol> -<blockquote> -<p>e.g. `grep --include=*.{h,c} -rnw / -e "from_kuid" will return string and filename that contains string.</p> -<p><img src="https://assets.garhve.com/pictures/screenshots/2022/09/grep_string.png" alt="image.png" /></p> -<ul> -<li><code>-r</code> or <code>-R</code> is recursive,</li> -<li><code>-n</code> is line number, and</li> -<li><code>-w</code> stands for match the whole word.</li> -<li><code>-l</code> (lower-case L) can be added to just give the file name of matching files.</li> -<li><code>-e</code> is the pattern used during the search</li> -</ul> -<p>Along with these, <code>--exclude</code>, <code>--include</code>, <code>--exclude-dir</code> flags could be used for efficient searching:</p> -<ul> -<li>This will only search through those files which have .c or .h extensions:</li> -</ul> -<pre data-lang="bash" style="background-color:#2e3440;color:#d8dee9;" class="language-bash "><code class="language-bash" data-lang="bash"><span style="color:#88c0d0;">grep</span><span> --include</span><span style="color:#81a1c1;">=</span><span style="color:#ebcb8b;">\*</span><span>.{c</span><span style="color:#eceff4;">,</span><span>h} -rnw </span><span style="color:#a3be8c;">'/path/to/somewhere/'</span><span> -e </span><span style="color:#a3be8c;">"pattern" -</span></code></pre> -<ul> -<li>This will exclude searching all the files ending with .o extension:</li> -</ul> -<pre data-lang="bash" style="background-color:#2e3440;color:#d8dee9;" class="language-bash "><code class="language-bash" data-lang="bash"><span style="color:#88c0d0;">grep</span><span> --exclude</span><span style="color:#81a1c1;">=</span><span style="color:#ebcb8b;">\*</span><span>.o -rnw </span><span style="color:#a3be8c;">'/path/to/somewhere/'</span><span> -e </span><span style="color:#a3be8c;">"pattern" -</span></code></pre> -<ul> -<li>For directories it's possible to exclude one or more directories using the <code>--exclude-dir</code> parameter. For example, this will exclude the dirs dir1/, dir2/ and all of them matching *.dst/:</li> -</ul> -<pre data-lang="bash" style="background-color:#2e3440;color:#d8dee9;" class="language-bash "><code class="language-bash" data-lang="bash"><span style="color:#88c0d0;">grep</span><span> --exclude-dir</span><span style="color:#81a1c1;">=</span><span>{dir1</span><span style="color:#eceff4;">,</span><span>dir2</span><span style="color:#eceff4;">,</span><span style="color:#81a1c1;">*</span><span>.dst} -rnw </span><span style="color:#a3be8c;">'/path/to/somewhere/'</span><span> -e </span><span style="color:#a3be8c;">"pattern" -</span></code></pre> -<p>more info could see <a href="https://ss64.com/bash/grep.html">man grep</a>.</p> -</blockquote> - -</p> - - - - - </div> - </section> -</body> - -<div class="footer"> -  © garhve -</div> - -</html> |