UNIX LINUX SHELL基础编程十二_unix_linux_其他

<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8"> <meta name="generator" content="pdf2htmlEX"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <link rel="stylesheet" href="https://static.pudn.com/base/css/base.min.css"> <link rel="stylesheet" href="https://static.pudn.com/base/css/fancy.min.css"> <link rel="stylesheet" href="https://static.pudn.com/prod/directory_preview_static/62897e4fce083560b82d01d5/raw.css"> <script src="https://static.pudn.com/base/js/compatibility.min.js"></script> <script src="https://static.pudn.com/base/js/pdf2htmlEX.min.js"></script> <script> try{ pdf2htmlEX.defaultViewer = new pdf2htmlEX.Viewer({}); }catch(e){} </script> <title></title> </head> <body> <div id="sidebar" style="display: none"> <div id="outline"> </div> </div> <div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62897e4fce083560b82d01d5/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">shell<span class="ff2 ls1">基础<span class="_ _0"> </span><span class="ff1">1</span>：文件安全与权限<span class="ff1"> </span></span></div><div class="t m0 x1 h2 y2 ff2 fs0 fc0 sc0 ls1 ws0">这里面可能用到用户管理方面的知识<span class="_ _1"></span>，可查看贴：<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y3 ff1 fs0 fc1 sc0 ls3 ws0">http://bbs.chinaunix.ne<span class="_ _1"></span>t/foru<span class="ls4">m/viewtopic.php?p=2923303#2923303<span class="_ _1"></span><span class="fc0 ls5"> </span></span></div><div class="t m0 x1 h2 y4 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 y5 ff2 fs0 fc0 sc0 ls1 ws0">主要有以下内容：<span class="ff1"> </span></div><div class="t m0 x2 h3 y6 ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m0 x3 h4 y7 ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m0 x4 h5 y8 ff2 fs2 fc2 sc0 ls1 ws0">文件权限位<span class="ff1 ls7"> </span></div><div class="t m0 x4 h5 y9 ff2 fs2 fc2 sc0 ls1 ws0">基本命令<span class="ff1 ls7"> </span></div><div class="t m0 x4 h5 ya ff1 fs2 fc2 sc0 ls8 ws1">chmod </div><div class="t m0 x4 h5 yb ff1 fs2 fc2 sc0 ls9 ws2">suid/guid </div><div class="t m0 x4 h5 yc ff1 fs2 fc2 sc0 lsa ws3">chown </div><div class="t m0 x4 h5 yd ff1 fs2 fc2 sc0 lsb ws4">chgrp </div><div class="t m0 x4 h5 ye ff1 fs2 fc2 sc0 lsc ws0">umask<span class="_ _2"> </span><span class="ff2 ls1">算法和用法</span><span class="ls7"> </span></div><div class="t m0 x4 h5 yf ff2 fs2 fc2 sc0 ls1 ws0">符号链接<span class="ff1"> </span></div><div class="t m0 x1 h2 y10 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 y11 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 y12 ff2 fs0 fc0 sc0 ls1 ws0">当创建一个文件的时候，系统保存了<span class="_ _1"></span>有关该文件的全部信息，包括：<span class="_ _1"></span><span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y13 ff2 fs0 fc0 sc0 ls1 ws0">•<span class="ff1"> <span class="_ _3"></span></span>文件的位置。<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y14 ff2 fs0 fc0 sc0 ls1 ws0">•<span class="ff1"> <span class="_ _3"></span></span>文件类型。<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y15 ff2 fs0 fc0 sc0 ls1 ws0">•<span class="ff1"> <span class="_ _3"></span></span>文件长度。<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y16 ff2 fs0 fc0 sc0 ls1 ws0">•<span class="ff1"> <span class="_ _3"></span></span>哪位用户拥有该文件，哪些用户可<span class="_ _1"></span>以访问该文件。<span class="ff1 ls5"> </span></div><div class="t m0 x1 h2 y17 ff2 fs0 fc0 sc0 ls1 ws0">•<span class="ff1 ls2"> i<span class="_ _4"></span></span><span class="lsd">节点。<span class="ff1 ls2"> </span></span></div><div class="t m0 x1 h2 y18 ff2 fs0 fc0 sc0 ls1 ws0">•<span class="ff1"> <span class="_ _3"></span></span>文件的修改时间。<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y19 ff2 fs0 fc0 sc0 ls1 ws0">•<span class="ff1"> <span class="_ _3"></span></span>文件的权限位。<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y1a ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 y1b ff2 fs0 fc0 sc0 ls1 ws0">让我们用<span class="_ _2"> </span><span class="ff1 lse">touch<span class="_ _5"> </span></span>命令创建一个文件：<span class="ff1"> </span></div><div class="t m0 x5 h3 y1c ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m0 x6 h4 y1d ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m0 x3 h5 y1e ff1 fs2 fc2 sc0 lsf ws5">$ touch temp </div><div class="t m0 x1 h2 y1f ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 y20 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 y21 ff2 fs0 fc0 sc0 ls1 ws0">创建了一个空文件，现在用<span class="_ _2"> </span><span class="ff1 ls10 ws6">ls -l<span class="_ _0"> </span></span>命令查看该目录下文件的属性（我这里用<span class="_ _1"></span>中文版<span class="ff1">)</span>：<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 y22 ff2 fs0 fc0 sc0 ls1 ws0">如下：<span class="ff1"> </span></div><div class="t m0 x7 h3 y23 ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m0 x6 h4 y24 ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m0 x3 h5 y25 ff1 fs2 fc2 sc0 ls1 ws7">[root@Linux_chenwy temp]# ls -l <span class="_ _3"></span> </div><div class="t m0 x3 h5 y26 ff2 fs2 fc2 sc0 ls1 ws0">总用量<span class="ff1 ls11 ws8"> 36 </span></div><div class="t m0 x3 h5 y27 ff1 fs2 fc2 sc0 ls8 ws9">-rw-r--r-- <span class="_ _3"></span> <span class="_ _4"></span>1 root <span class="_ _3"></span> <span class="_ _3"></span> root <span class="_ _4"></span> <span class="_ _3"></span> <span class="_ _3"></span> <span class="_ _4"></span>34890 10<span class="_ _2"> </span><span class="ff2 ls1 ws0">月</span><span class="ls12 wsa"> <span class="_ _4"></span>19 2<span class="_ _6"></span>0:17 httpd.conf <span class="_ _3"></span> </span></div><div class="t m0 x3 h5 y28 ff1 fs2 fc2 sc0 ls13 wsb">-rw-r--r-- <span class="_ _4"></span> <span class="_ _3"></span>1 root <span class="_ _3"></span> <span class="_ _4"></span> root <span class="_ _3"></span> <span class="_ _3"></span> <span class="_ _4"></span> <span class="_ _3"></span> <span class="_ _3"></span> <span class="_ _4"></span>0 10<span class="_ _2"> </span><span class="ff2 ls1 ws0">月</span><span class="ls14 wsc"> <span class="_ _4"></span>19 20:<span class="_ _6"></span>16 temp </span></div><div class="t m0 x1 h2 y29 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h3 y2a ff1 fs1 fc0 sc0 ls1 ws0"> </div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div> </body> </html>

<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62897e4fce083560b82d01d5/bg2.jpg"><div class="t m2 x6 h4 y2b ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h5 y2c ff2 fs2 fc2 sc0 ls1 ws0">总用量<span class="ff1 ls11 ws8"> 36</span><span class="ls6">：是<span class="_ _2"> </span><span class="ff1 ls15">ls<span class="_ _2"> </span></span></span>所列出的入口占用空间的字节数<span class="ff1">(</span>以<span class="_ _2"> </span><span class="ff1">K<span class="_ _2"> </span></span>为单位<span class="ff1">)</span>。<span class="ff1 ls7"> </span></div><div class="t m2 x3 h5 y2d ff1 fs2 fc2 sc0 ls1 ws0">1<span class="_ _2"> </span><span class="ff2">该文件硬链接的数目。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y2e ff1 fs2 fc2 sc0 lsf ws0">root<span class="ff2 ls1">：文件属主。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y2f ff1 fs2 fc2 sc0 lsf ws0">root<span class="ff2 ls1">：文件属组（一般是文件属主所在的缺省组。<span class="_ _7"></span>）<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y30 ff1 fs2 fc2 sc0 ls11 ws0">34890<span class="ff2 ls1">：字节来表示的文件长度，记住，不是<span class="_ _2"> </span><span class="ff1">K<span class="_ _2"> </span></span>字节！</span><span class="ls16"> </span></div><div class="t m2 x3 h5 y8 ff1 fs2 fc2 sc0 ls11 ws0">10<span class="_ _2"> </span><span class="ff2 ls1">月</span><span class="wsd"> 19 <span class="_ _8"></span>20:17<span class="ff2 ls1 ws0">：件的更新时间。<span class="ff1 ls7"> </span></span></span></div><div class="t m2 x3 h5 y9 ff1 fs2 fc2 sc0 ls1 ws7">temp or httd.conf <span class="_ _3"></span><span class="ff2 ws0">：件名。<span class="ff1"> </span></span></div><div class="t m2 x1 h2 y31 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h3 y32 ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m2 x6 h4 y33 ff3 fs2 fc0 sc0 ls17 ws0">sunsroad <span class="_ _3"></span><span class="ff2 sc1 ls1">写到</span><span class="ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h5 y34 ff1 fs2 fc3 sc0 ls1 ws0"> </div><div class="t m2 x3 h5 y35 ff3 fs2 fc3 sc0 ls18 ws0">BTW:<span class="ff2 sc2 ls6">要检查该目录所有文件占用<span class="_ _1"></span>的空间应该用这个命<span class="_ _1"></span>令：<span class="ff3 sc0 ls19">du</span><span class="ls1">。<span class="ff1 sc0 ls7"> </span></span></span></div><div class="t m2 x3 h5 y36 ff2 fs2 fc3 sc0 ls1 ws0">譬如说前面说的<span class="_ _2"> </span><span class="ff1 ls1a">36<span class="_ _2"> </span></span>是如何计算出来：<span class="ff1 ls7"> </span></div><div class="t m2 x3 h5 y37 ff2 fs2 fc3 sc0 ls1 ws0">首先我们要先了解你所用的文件系统的<span class="_ _9"> </span><span class="ff1 ls1b wse">IO BLOCK</span>（中文叫作簇）为多少，在你所使用的这个</div><div class="t m2 x3 h5 y38 ff2 fs2 fc3 sc0 ls1 ws0">文件系统的<span class="_ _2"> </span><span class="ff1 ls17 wsf">IO BLOCK<span class="_ _2"> </span></span>大小是<span class="_ _2"> </span><span class="ff1 ls9 ws10">4096 Bytes</span>。<span class="ff1 ls7"> </span></div><div class="t m2 x3 h5 y39 ff1 fs2 fc3 sc0 ls1 ws0"> </div><div class="t m2 x3 h6 y3a ff2 fs2 fc3 sc0 ls1c ws0">他意义是文件系统最小的读<span class="_ _1"></span>写及分配单位，每次读写操作你都不<span class="_ _1"></span>能小于这个尺寸。即使你的文</div><div class="t m2 x3 h6 y3b ff2 fs2 fc3 sc0 ls1c ws0">件是只有一个字节。而且文<span class="_ _1"></span>件在硬盘上的存储也是以这个为单位<span class="_ _1"></span>，就是说如果文件尺寸小于这</div><div class="t m2 x3 h5 y3c ff2 fs2 fc3 sc0 ls1 ws0">个值，那么它在磁盘上占用的空间就是<span class="_ _2"> </span><span class="ff1 ls11">4096<span class="_ _2"> </span></span>字节。<span class="ff1 ls7"> </span></div><div class="t m2 x3 h5 y3d ff1 fs2 fc3 sc0 ls1 ws0"> </div><div class="t m2 x3 h5 y3e ff2 fs2 fc3 sc0 ls1 ws0">占用空间的具体算法是：<span class="_ _7"></span>（进一<span class="_ _1"></span>（文件尺寸<span class="ff1 ls14">/4096</span>）<span class="_ _7"></span><span class="ls1d">）×<span class="ff1 ls1a">4096</span><span class="ls1">。根据这个你就可以计算出你所列</span></span></div><div class="t m2 x3 h5 y3f ff2 fs2 fc3 sc0 ls1 ws0">举的例子中的文件的空间使用状况：<span class="ff1 ls11">34890<span class="_"> </span></span>除以<span class="_ _a"> </span><span class="ff1 ls11">4096</span>，大约等于<span class="_ _a"> </span><span class="ff1 ls11">8.5</span>，进一法取得为<span class="_ _9"> </span><span class="ff1">9</span>，就</div><div class="t m2 x3 h5 y40 ff2 fs2 fc3 sc0 ls1 ws0">是说文件在磁盘上占用了<span class="_ _0"> </span><span class="ff1">9<span class="_ _5"> </span></span>个<span class="_ _0"> </span><span class="ff1 ls1e">BLOCk</span>，每个<span class="_ _5"> </span><span class="ff1 ls1e">BLOCK<span class="_ _0"> </span></span>为<span class="_ _5"> </span><span class="ff1 ls11">4K</span>，所以这两个文件占用的空间就是</div><div class="t m2 x3 h5 y41 ff1 fs2 fc3 sc0 ls11 ws0">36K<span class="ff2 ls1">。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y42 ff1 fs2 fc3 sc0 ls1 ws0"> </div><div class="t m2 x3 h5 y43 ff2 fs2 fc3 sc0 ls1 ws0">这个规则也适合于目录，不过不会出现为<span class="_ _2"> </span><span class="ff1">0<span class="_ _2"> </span></span>的目录，即使是空目录<span class="ff1"> </span></div><div class="t m2 x1 h2 y44 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y45 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y46 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y47 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y48 ff3 fs0 fc0 sc0 ls1f ws0">-rw-r--r-- <span class="_ _3"></span><span class="ff2 sc1 ls1">：这是该文件的权限位<span class="_ _6"></span>。</span><span class="ff1 ls5"> </span></div><div class="t m2 x1 h2 y49 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y4a ff2 fs0 fc0 sc0 ls1 ws0">第一个横杠：<span class="_ _8"></span>指定文件类型<span class="_ _1"></span><span class="ff1">,<span class="ff2">表示该文件是一个普通文件。<span class="_ _b"></span><span class="ff1">(<span class="ff2">所创建的文件绝大多数都是普<span class="_ _1"></span>通文件</span></span></span></span></div><div class="t m2 x1 h2 y4b ff2 fs0 fc0 sc0 ls1 ws0">或符号链接文件<span class="ff1">)</span>。<span class="ff1 ls2"> </span></div><div class="t m2 x1 h2 y4c ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y4d ff2 fs0 fc0 sc0 ls1 ws0">除去最前面的横杠，一共是<span class="_ _5"> </span><span class="ff1">9<span class="_ _9"> </span></span>个字符，他们分别对应<span class="_ _9"> </span><span class="ff1">9<span class="_"> </span></span>个权限<span class="_ _1"></span>位。通过这些权限位，可以设定</div><div class="t m2 x1 h2 y4e ff2 fs0 fc0 sc0 ls1 ws0">用户对文件的访问权限。对这两个文<span class="_ _1"></span>件的精确解释是：<span class="ff1"> </span></div><div class="t m2 x8 h3 y4f ff1 fs1 fc0 sc0 ls1 ws0"> </div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>

<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62897e4fce083560b82d01d5/bg3.jpg"><div class="t m2 x6 h4 y2b ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h5 y2c ff1 fs2 fc2 sc0 ls20 ws0">rw-<span class="ff2 ls1">：前三位，文件属主可读、写</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y2d ff1 fs2 fc2 sc0 ls21 ws0">r--<span class="ff2 ls1">：中间三位<span class="ff1">,</span>组用户可读</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y2e ff1 fs2 fc2 sc0 ls21 ws0">r--<span class="ff2 ls1">：最后三位<span class="ff1">,</span>其他用户只可读<span class="ff1"> </span></span></div><div class="t m2 x1 h2 y50 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y51 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h7 y52 ff2 fs0 fc0 sc0 ls1 ws0">在创建的时候并未给属主赋予执行权<span class="_ _1"></span>限，在用户创建文件时，系统不<span class="_ _1"></span>会自动地设置执行权限位。</div><div class="t m2 x1 h2 y53 ff2 fs0 fc0 sc0 ls1 ws0">这是出于加强系统安全的考虑<span class="ff1 ls2"> </span></div><div class="t m2 x1 h2 y54 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h8 y55 ff3 fs0 fc0 sc0 ls22 ws0">BTW<span class="ff2 sc1 ls1">：<span class="_ _c"></span>文件的属主组并不一定就是所有者<span class="_ _6"></span>所在的缺省组，<span class="_ _c"></span>而可以是任<span class="_ _6"></span>何一个跟该文件所有者无</span></div><div class="t m2 x1 h8 y56 ff2 fs0 fc0 sc1 ls1 ws0">关的用户组。为了方便，还是<span class="_ _6"></span>统称属主，属组和其它<span class="ff3 sc0"> </span></div><div class="t m2 x1 h8 y57 ff3 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y58 ff2 fs0 fc0 sc1 ls1 ws0">文件类型<span class="ff1 sc0 ls2"> </span></div><div class="t m2 x1 h2 y59 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y5a ff2 fs0 fc0 sc0 ls1 ws0">前面提到的第一条横杠，表示该文件<span class="_ _1"></span>是普通文件型<span class="ff1 ls2"> </span></div><div class="t m2 x1 h2 y5b ff2 fs0 fc0 sc0 ls1 ws0">文件类型有七种，它可以从<span class="_ _2"> </span><span class="ff1 ls10 ws6">ls -l<span class="_ _0"> </span></span>命令所列出的结果的第一位看出<span class="ff1 ls23 ws11">. </span></div><div class="t m2 x1 h2 y5c ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y5d ff2 fs0 fc0 sc0 ls1 ws0">七种类型：<span class="ff1"> </span></div><div class="t m2 x9 h3 y5e ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m2 x6 h4 y5f ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h5 y60 ff1 fs2 fc2 sc0 ls24 ws0">d <span class="_ _3"></span><span class="ff2 ls1">目录。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y61 ff1 fs2 fc2 sc0 ls15 ws0">l <span class="_ _3"></span><span class="ff2 ls1">符号链接<span class="ff1">(</span>指<span class="_ _1"></span>向另一个文件<span class="ff1">)</span>。<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y62 ff1 fs2 fc2 sc0 ls8 ws0">s <span class="_ _3"></span><span class="ff2 ls1">套接字文件。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y63 ff1 fs2 fc2 sc0 ls24 ws0">b <span class="_ _3"></span><span class="ff2 ls1">块设备文件。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y64 ff1 fs2 fc2 sc0 ls8 ws0">c <span class="_ _3"></span><span class="ff2 ls1">字符设备文件。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y65 ff1 fs2 fc2 sc0 ls24 ws0">p <span class="_ _3"></span><span class="ff2 ls1">命名管道文件。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y66 ff1 fs2 fc2 sc0 ls25 ws0">- <span class="_ _3"></span><span class="ff2 ls1">普通文件，或者更准确地说，不属于以上几种类型的文件。<span class="ff1"> </span></span></div><div class="t m2 x1 h2 y67 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y68 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y69 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y6a ff2 fs0 fc0 sc1 ls1 ws0">文件的权限位中中每一组字符<span class="_ _6"></span>中含有三个权限位：<span class="ff1 sc0"> </span></div><div class="t m2 xa h3 y6b ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m2 x6 h4 y6c ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h5 y6d ff1 fs2 fc2 sc0 lsc ws0">r <span class="_ _3"></span><span class="ff2 ls1">读权限</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y6e ff1 fs2 fc2 sc0 ls26 ws0">w <span class="_ _3"></span><span class="ff2 ls1">写<span class="ff1">/</span>更改权限</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y6f ff1 fs2 fc2 sc0 ls27 ws0">x <span class="_ _3"></span><span class="ff2 ls1">执行该脚本或程序的权限<span class="ff1"> </span></span></div><div class="t m2 x1 h2 y70 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y71 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y72 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y73 ff2 fs0 fc0 sc0 ls1 ws0">如：<span class="ff1"> </span></div><div class="t m2 xb h3 y74 ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m2 x6 h4 y75 ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>

<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62897e4fce083560b82d01d5/bg4.jpg"><div class="t m2 x3 h5 y76 ff1 fs2 fc2 sc0 ls25 ws12">r-- --- --- <span class="_ _3"></span><span class="ff2 ls1 ws0">文文件属主可读，但不能写或执行<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y77 ff1 fs2 fc2 sc0 ls25 ws12">r-- r-- --- <span class="_ _4"></span><span class="ff2 ls1 ws0">文文件属主和属组用户<span class="ff1">(</span>一般来说，是文件属主所在的缺省组<span class="ff1">)</span>可读<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y78 ff1 fs2 fc2 sc0 ls28 ws13">r-- r-- r- - <span class="_ _4"></span><span class="ff2 ls1 ws0">文任何用户都可读，但不能写或执行<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y79 ff1 fs2 fc2 sc0 ls29 ws14">rwx r-- r- - <span class="_ _4"></span><span class="ff2 ls1 ws0">文文件属主可读、写、执行，属组用户和其他用户只可读<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y7a ff1 fs2 fc2 sc0 ls1b ws15">rwx r-<span class="_ _1"></span>x --- <span class="_ _4"></span><span class="ff2 ls1 ws0">文文件属主可读、写、执行，属组用户可读、执<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y7b ff1 fs2 fc2 sc0 ls2a ws16">rwx r-<span class="_ _1"></span>x r- x <span class="_ _4"></span><span class="ff2 ls1 ws0">文文件属主可读、写、执行，属组用户和其他用户可读、执行<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y7c ff1 fs2 fc2 sc0 ls9 ws10">rw- rw- --- <span class="_ _4"></span><span class="ff2 ls1 ws0">文文件属主和属组用户可读、写<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y7d ff1 fs2 fc2 sc0 ls2b ws17">rw- rw- r- - <span class="_ _4"></span><span class="ff2 ls1 ws0">文文件属主和属组用户可读、写，其他用户可读<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y7e ff1 fs2 fc2 sc0 ls9 ws10">rw- rw- --- <span class="_ _4"></span><span class="ff2 ls1 ws0">文文件属主和属组用户及其他用户读可以读、写，慎用这种权限<span class="ff1 ls7"> </span></span></div><div class="t m2 x3 h5 y7f ff2 fs2 fc2 sc0 ls1 ws0">设置，因为任何用户都可以写入该文件<span class="ff1"> </span></div><div class="t m2 x1 h3 y80 ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m2 x6 h4 y81 ff3 fs2 fc0 sc0 ls17 ws0">sunsroad <span class="_ _3"></span><span class="ff2 sc1 ls1">写到</span><span class="ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h6 y82 ff2 fs2 fc3 sc0 ls1c ws0">文件的所有者组并非是文件<span class="_ _1"></span>所有者所在的缺省组，而可以是任何<span class="_ _1"></span>一个跟该文件所有者无关的用</div><div class="t m2 x3 h5 y83 ff2 fs2 fc3 sc0 ls1 ws0">户组。<span class="ff1"> </span></div><div class="t m2 x1 h2 y84 ff2 fs0 fc0 sc1 ls1 ws0">使用<span class="_ _0"> </span><span class="ff3 sc0 ls2c">chmod<span class="_ _0"> </span></span>来改变<span class="_ _6"></span>权限位<span class="ff1 sc0 ls2"> </span></div><div class="t m2 x1 h2 y85 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y86 ff2 fs0 fc0 sc0 ls1 ws0">这一命令有符号模式和绝对模式。<span class="_ _1"></span><span class="ff1 ls2"> </span></div><div class="t m2 x1 h2 y87 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y88 ff2 fs0 fc0 sc1 ls1 ws0">符号模式<span class="ff1 sc0 ls2"> </span></div><div class="t m2 x1 h2 y89 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y8a ff1 fs0 fc0 sc0 ls4 ws0">chmod<span class="_ _0"> </span><span class="ff2 ls1">命令的一般格式为：</span><span class="ls2"> </span></div><div class="t m2 x1 h2 y8b ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y8c ff3 fs0 fc0 sc0 ls2d ws18">chmod [who] operator [permis<span class="_ _1"></span>sion] filename<span class="ff1 ls2 ws0"> </span></div><div class="t m2 x1 h2 y8d ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y8e ff3 fs0 fc0 sc0 ls2e ws19">w h o<span class="_ _2"> </span><span class="ff2 sc1 ls2f ws0">的含义是：<span class="ff1 sc0 ls1"> </span></span></div><div class="t m2 xc h3 y8f ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m2 x6 h4 y90 ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h5 y91 ff1 fs2 fc2 sc0 ls30 ws0">u <span class="_ _3"></span><span class="ff2 ls1">文件属主权限。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y92 ff1 fs2 fc2 sc0 ls24 ws0">g <span class="_ _3"></span><span class="ff2 ls1">属组用户权限。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y93 ff1 fs2 fc2 sc0 lsf ws0">o <span class="_ _3"></span><span class="ff2 ls1">其他用户权限。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y94 ff1 fs2 fc2 sc0 ls31 ws0">a <span class="_ _3"></span><span class="ff2 ls1">所有用户<span class="ff1">(</span>文件属主、属组用户及其他用户<span class="ff1">)</span>。<span class="ff1"> </span></span></div><div class="t m2 x1 h2 y95 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y96 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y97 ff3 fs0 fc0 sc0 ls23 ws1a">o p e r a t o r<span class="_ _2"> </span><span class="ff2 sc1 ls1 ws0">的含义：<span class="ff1 sc0"> </span></span></div><div class="t m2 xd h3 y98 ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m2 x6 h4 y99 ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m2 x3 h5 y9a ff1 fs2 fc2 sc0 ls26 ws0">+ <span class="_ _3"></span><span class="ff2 ls1">增加权限。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y9b ff1 fs2 fc2 sc0 ls25 ws0">- <span class="_ _3"></span><span class="ff2 ls1">取消权限。</span><span class="ls7"> </span></div><div class="t m2 x3 h5 y9c ff1 fs2 fc2 sc0 ls26 ws0">= <span class="_ _3"></span><span class="ff2 ls1">设定权限。<span class="ff1"> </span></span></div><div class="t m2 x1 h2 y9d ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m2 x1 h2 y9e ff1 fs0 fc0 sc0 ls1 ws0"> </div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>

<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62897e4fce083560b82d01d5/bg5.jpg"><div class="t m0 x1 h3 y1 ff3 fs0 fc0 sc0 ls32 ws1b">p e r m i s s i o n<span class="_ _2"> </span><span class="ff2 sc1 ls1 ws0">的含义：<span class="ff1 sc0"> <span class="_ _3"></span><span class="fs1"> </span></span></span></div><div class="t m0 x6 h4 y9f ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m0 x3 h5 ya0 ff1 fs2 fc2 sc0 lsc ws0">r <span class="_ _3"></span><span class="ff2 ls1">读权限。</span><span class="ls7"> </span></div><div class="t m0 x3 h5 ya1 ff1 fs2 fc2 sc0 ls26 ws0">w <span class="_ _3"></span><span class="ff2 ls1">写权限。</span><span class="ls7"> </span></div><div class="t m0 x3 h5 ya2 ff1 fs2 fc2 sc0 ls27 ws0">x <span class="_ _3"></span><span class="ff2 ls1">执行权限。</span><span class="ls7"> </span></div><div class="t m0 x3 h5 ya3 ff1 fs2 fc2 sc0 ls8 ws0">s <span class="_ _3"></span><span class="ff2 ls1">文件属主和组<span class="_ _2"> </span></span><span class="ls33">set<span class="_ _1"></span>-ID<span class="ff2 ls1">。</span><span class="ls16"> </span></span></div><div class="t m0 x3 h5 ya4 ff1 fs2 fc2 sc0 ls34 ws0">t <span class="_ _3"></span><span class="ff2 ls1">粘性位<span class="ff1">*</span>。</span><span class="ls7"> </span></div><div class="t m0 x3 h5 ya5 ff1 fs2 fc2 sc0 ls15 ws0">l <span class="_ _3"></span><span class="ff2 ls1">给文件加锁，<span class="_ _1"></span>使其他用户无法访问。<span class="ff1 ls7"> </span></span></div><div class="t m0 x3 h5 ya6 ff1 fs2 fc2 sc0 ls30 ws0">u,g,o <span class="_ _3"></span><span class="ff2 ls1">针对文件属主、属组用户及其他用户的操作。</span><span class="ls7"> </span></div><div class="t m0 x3 h5 ya7 ff1 fs2 fc2 sc0 ls1 ws0"> </div><div class="t m0 x3 h5 ya8 ff1 fs2 fc2 sc0 ls1 ws0">*<span class="ff2">在列文件或目录时，<span class="_ _c"></span>有时会遇到<span class="_ _c"></span>“<span class="ff1 ls7"> t<span class="_ _8"></span><span class="ff2 ls35">”位<span class="_ _4"></span>。<span class="_ _7"></span><span class="ls1">“<span class="ff1">t</span>”<span class="_ _c"></span>代表了粘性位。<span class="_ _c"></span>如果在一个目录上出现<span class="_ _c"></span>“<span class="ff1">t</span><span class="ls35">”位<span class="_ _4"> </span>，</span></span></span></span></span></div><div class="t m0 x3 h6 ya9 ff2 fs2 fc2 sc0 ls1 ws0">这就意味着该目录中的文件只有其属主才可以删除，<span class="_ _1"></span>即使某个属组用户具有和属主同等的权限。</div><div class="t m0 x3 h5 yaa ff2 fs2 fc2 sc0 ls1 ws0">不过有的系统在这一规则上并不十分严格。<span class="ff1 ls7"> </span></div><div class="t m0 x3 h5 yab ff1 fs2 fc2 sc0 ls1 ws0"> </div><div class="t m0 x3 h5 yac ff2 fs2 fc2 sc0 ls1 ws0">如果在文件列表时看到“<span class="ff1 ls7"> t<span class="_ _8"></span><span class="ff2 ls1">”<span class="_ _7"></span>，那么这就意味着该脚本或程序在执行时会被放在交换区<span class="ff1">(</span>虚存<span class="ff1">)</span>。<span class="ff1"> </span></span></span></div><div class="t m0 x1 h2 yad ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yae ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yaf ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yb0 ff2 fs0 fc0 sc0 ls1 ws0">对<span class="ff1 ls36">"t"</span>还没弄清楚这是<span class="_ _1"></span><span class="ff1 ls2d">"sunsroad"<span class="ff2 lsd">的解释：</span><span class="ls1"> </span></span></div><div class="t m0 xe h3 yb1 ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m0 x6 h4 yb2 ff3 fs2 fc0 sc0 ls17 ws0">sunsroad <span class="_ _3"></span><span class="ff2 sc1 ls1">写到</span><span class="ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m0 x3 h5 yb3 ff1 fs2 fc3 sc0 ls29 ws0">"t"<span class="ff2 ls6">权限用在文件上面是没有<span class="_ _1"></span>意义的，不是什么在<span class="_ _1"></span>交换区的概念，它跟<span class="_ _1"></span>文件的执行没有关系，而</span></div><div class="t m0 x3 h5 yb4 ff2 fs2 fc3 sc0 ls1 ws0">主要是为了文件共享设置的。<span class="ff1 ls7"> </span></div><div class="t m0 x1 h2 yb5 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yb6 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yb7 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yb8 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yb9 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yba ff2 fs0 fc0 sc0 ls1 ws0">例如<span class="ff1 ls2"> </span></div><div class="t m0 x1 h3 ybb ff1 fs1 fc0 sc0 ls1 ws0"> </div><div class="t m0 x6 h4 ybc ff2 fs2 fc0 sc1 ls6 ws0">代码<span class="ff3 sc0 ls1">:<span class="ff1 fs3"> </span></span></div><div class="t m0 x3 h5 ybd ff1 fs2 fc2 sc0 ls2b ws17">chmod a-x temp //rw- rw-<span class="_ _1"></span> rw- <span class="_ _3"></span><span class="ff2 ls1 ws0">收回所有<span class="_ _1"></span>用户的执行权限<span class="ff1 ls7"> </span></span></div><div class="t m0 x3 h5 ybe ff1 fs2 fc2 sc0 ls34 ws1c">chmod og-w temp //rw- r-- r- - <span class="_ _4"></span><span class="ff2 ls1 ws0">收回属组用户和其他用户的写权限<span class="ff1 ls7"> </span></span></div><div class="t m0 x3 h5 ybf ff1 fs2 fc2 sc0 ls28 ws13">chmod g+w temp //rw- rw- r- - <span class="_ _4"></span><span class="ff2 ls1 ws0">赋予属组用户写权限<span class="ff1 ls7"> </span></span></div><div class="t m0 x3 h5 yc0 ff1 fs2 fc2 sc0 ls13 wsb">chmod u+x temp //rwx rw- r- - <span class="_ _4"></span><span class="ff2 ls1 ws0">赋予文件属主执行权限<span class="ff1 ls7"> </span></span></div><div class="t m0 x3 h5 yc1 ff1 fs2 fc2 sc0 lsf ws5">chmod go+x temp //rwx rwx r- x <span class="_ _4"></span><span class="ff2 ls1 ws0">赋予属组用户和其他用户执行权限<span class="ff1"> </span></span></div><div class="t m0 x1 h2 yc2 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yc3 ff1 fs0 fc0 sc0 ls1 ws0"> </div><div class="t m0 x1 h2 yc4 ff2 fs0 fc0 sc0 ls1 ws0">举如<span class="ff1 ls2"> </span></div><div class="t m0 x1 h2 yc5 ff1 fs0 fc0 sc0 ls1 ws0"> </div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>

UNIX LINUX SHELL基础编程 十二

UNIX LINUX SHELL基础编程十二