{"id":329,"date":"2025-11-02T20:50:37","date_gmt":"2025-11-02T12:50:37","guid":{"rendered":"https:\/\/www.garfield-blog.top\/?p=329"},"modified":"2025-11-02T21:14:12","modified_gmt":"2025-11-02T13:14:12","slug":"shell%e5%9f%ba%e7%a1%80%e8%af%ad%e6%b3%95","status":"publish","type":"post","link":"https:\/\/www.garfield-blog.top\/?p=329","title":{"rendered":"\u3010\u7f16\u7a0b\u8bed\u8a00\u5b66\u4e60\u3011Shell\u57fa\u7840\u8bed\u6cd5"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">1. \u7b80\u4ecb<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1.1 Shell \u73af\u5883<\/h3>\n\n\n\n<p><code>Shell<\/code> \u7f16\u7a0b\u8ddf <code>JavaScript<\/code>\u3001<code>php<\/code> \u7f16\u7a0b\u4e00\u6837\uff0c\u53ea\u8981\u6709\u4e00\u4e2a\u80fd\u7f16\u5199\u4ee3\u7801\u7684\u6587\u672c\u7f16\u8f91\u5668\u548c\u4e00\u4e2a\u80fd\u89e3\u91ca\u6267\u884c\u7684\u811a\u672c\u89e3\u91ca\u5668\u5c31\u53ef\u4ee5\u4e86\u3002<code>#!<\/code> \u544a\u8bc9\u7cfb\u7edf\u5176\u540e\u8def\u5f84\u6240\u6307\u5b9a\u7684\u7a0b\u5e8f\u5373\u662f\u89e3\u91ca\u6b64\u811a\u672c\u6587\u4ef6\u7684 <code>Shell<\/code> \u7a0b\u5e8f\u3002<\/p>\n\n\n\n<p><code>Linux<\/code> \u7684 <code>Shell<\/code> \u79cd\u7c7b\u4f17\u591a\uff0c\u5e38\u89c1\u7684\u6709\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>Bourne Shell<\/code>\uff08<code>\/usr\/bin\/sh<\/code>\u6216<code>\/bin\/sh<\/code>\uff09<\/li>\n\n\n\n<li><code>Bourne Again Shell<\/code>\uff08<code>\/bin\/Bash<\/code>\uff09<\/li>\n\n\n\n<li><code>C Shell<\/code>\uff08<code>\/usr\/bin\/csh<\/code>\uff09<\/li>\n\n\n\n<li><code>K Shell<\/code>\uff08<code>\/usr\/bin\/ksh<\/code>\uff09<\/li>\n\n\n\n<li><code>Shell for Root<\/code>\uff08<code>\/sbin\/sh<\/code>\uff09<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">2. \u53d8\u91cf<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">2.1 \u53d8\u91cf\u5b9a\u4e49\u8d4b\u503c<\/h3>\n\n\n\n<p>\u5b9a\u4e49\u53d8\u91cf\u65f6\uff0c\u53d8\u91cf\u540d\u4e0d\u52a0\u7f8e\u5143\u7b26\u53f7\uff08$\uff09\uff0c\u6ce8\u610f\uff0c<strong>\u53d8\u91cf\u540d\u548c\u7b49\u53f7\u4e4b\u95f4\u4e0d\u80fd\u6709\u7a7a\u683c<\/strong>\uff0c\u8fd9\u53ef\u80fd\u548c\u4f60\u719f\u6089\u7684\u6240\u6709\u7f16\u7a0b\u8bed\u8a00\u90fd\u4e0d\u4e00\u6837\u3002\u6709\u7a7a\u683c\u4f1a\u51fa\u9519<\/p>\n\n\n\n<p>\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>variableName=\"value\"<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.2 \u4f7f\u7528\u53d8\u91cf<\/h3>\n\n\n\n<p>\u4f7f\u7528\u4e00\u4e2a\u5b9a\u4e49\u8fc7\u7684\u53d8\u91cf\uff0c\u53ea\u8981\u5728\u53d8\u91cf\u540d\u524d\u9762\u52a0\u7f8e\u5143\u7b26\u53f7<code>$<\/code>\u5373\u53ef<\/p>\n\n\n\n<p>\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>your_name=\"lalal\"\necho $your_name\necho ${your_name}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.3 \u53ea\u8bfb\u53d8\u91cf<\/h3>\n\n\n\n<p>\u4f7f\u7528 <code>readonly<\/code> \u547d\u4ee4\u53ef\u4ee5\u5c06\u53d8\u91cf\u5b9a\u4e49\u4e3a\u53ea\u8bfb\u53d8\u91cf\uff0c\u53ea\u8bfb\u53d8\u91cf\u7684\u503c\u4e0d\u80fd\u88ab\u6539\u53d8<\/p>\n\n\n\n<p>\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\n\n# \u4e0b\u9762\u7684\u4f8b\u5b50\u5c1d\u8bd5\u66f4\u6539\u53ea\u8bfb\u53d8\u91cf\uff0c\u7ed3\u679c\u62a5\u9519\ntest=\"a\"\nreadonly test\ntest=\"b\"<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.4 \u5220\u9664\u53d8\u91cf<\/h3>\n\n\n\n<p>\u4f7f\u7528 <code>unset<\/code> \u547d\u4ee4\u53ef\u4ee5\u5220\u9664\u53d8\u91cf\uff0c\u53d8\u91cf\u88ab\u5220\u9664\u540e\u4e0d\u80fd\u518d\u6b21\u4f7f\u7528\uff0c\u540c\u65f6<code>unset<\/code> \u547d\u4ee4\u4e0d\u80fd\u5220\u9664\u53ea\u8bfb\u53d8\u91cf\u3002<\/p>\n\n\n\n<p>\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>unset variable_name<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.5 \u7279\u6b8a\u53d8\u91cf<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u53d8\u91cf<\/th><th>\u542b\u4e49<\/th><\/tr><\/thead><tbody><tr><td><code>$0<\/code><\/td><td>\u5f53\u524d\u811a\u672c\u7684\u6587\u4ef6\u540d<\/td><\/tr><tr><td><code>$n<\/code><\/td><td>\u4f20\u9012\u7ed9\u811a\u672c\u6216\u51fd\u6570\u7684\u53c2\u6570\u3002n \u662f\u4e00\u4e2a\u6570\u5b57\uff0c\u8868\u793a\u7b2c\u51e0\u4e2a\u53c2\u6570\u3002\u4f8b\u5982\uff0c\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f<code>$1<\/code>\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u662f<code>$2<\/code>\u3002<\/td><\/tr><tr><td><code>$#<\/code><\/td><td>\u4f20\u9012\u7ed9\u811a\u672c\u6216\u51fd\u6570\u7684\u53c2\u6570\u4e2a\u6570\u3002<\/td><\/tr><tr><td><code>$*<\/code><\/td><td>\u4f20\u9012\u7ed9\u811a\u672c\u6216\u51fd\u6570\u7684\u6240\u6709\u53c2\u6570\u3002<\/td><\/tr><tr><td><code>$@<\/code><\/td><td>\u4f20\u9012\u7ed9\u811a\u672c\u6216\u51fd\u6570\u7684\u6240\u6709\u53c2\u6570\u3002\u88ab\u53cc\u5f15\u53f7(&#8221; &#8220;)\u5305\u542b\u65f6\uff0c\u4e0e <code>$*<\/code> \u7a0d\u6709\u4e0d\u540c<\/td><\/tr><tr><td><code>$?<\/code><\/td><td>\u4e0a\u4e2a\u547d\u4ee4\u7684\u9000\u51fa\u72b6\u6001\uff0c\u6216\u51fd\u6570\u7684\u8fd4\u56de\u503c\u3002<\/td><\/tr><tr><td><code>$$<\/code><\/td><td>\u5f53\u524dShell\u8fdb\u7a0bID\u3002\u5bf9\u4e8e Shell \u811a\u672c\uff0c\u5c31\u662f\u8fd9\u4e9b\u811a\u672c\u6240\u5728\u7684\u8fdb\u7a0bID\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><code>$*<\/code> \u548c <code>$@<\/code> \u7684\u533a\u522b<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>$*<\/code> \u548c <code>$@<\/code> \u90fd\u8868\u793a\u4f20\u9012\u7ed9\u51fd\u6570\u6216\u811a\u672c\u7684\u6240\u6709\u53c2\u6570\uff0c\u4e0d\u88ab\u53cc\u5f15\u53f7(&#8221; &#8220;)\u5305\u542b\u65f6\uff0c\u90fd\u4ee5<code>\"$1\" \"$2\" \u2026 \"$n\"<\/code> \u7684\u5f62\u5f0f\u8f93\u51fa\u6240\u6709\u53c2\u6570\u3002\u4f46\u662f\u5f53\u5b83\u4eec\u88ab\u53cc\u5f15\u53f7(&#8221; &#8220;)\u5305\u542b\u65f6\uff0c&#8221;<code>$*<\/code>&#8221; \u4f1a\u5c06\u6240\u6709\u7684\u53c2\u6570\u4f5c\u4e3a\u4e00\u4e2a\u6574\u4f53\uff0c\u4ee5&#8221;<code>$1 $2 \u2026 $n<\/code>&#8220;\u7684\u5f62\u5f0f\u8f93\u51fa\u6240\u6709\u53c2\u6570\uff1b&#8221;<code>$@<\/code>&#8221; \u4f1a\u5c06\u5404\u4e2a\u53c2\u6570\u5206\u5f00\uff0c\u4ee5<code>\"$1\" \"$2\" \u2026 \"$n\"<\/code> \u7684\u5f62\u5f0f\u8f93\u51fa\u6240\u6709\u53c2\u6570\u3002<\/li>\n\n\n\n<li>\u793a\u4f8b\uff1a <\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\n\necho \"print each param from \\\"\\$*\\\"\"\nfor var in \"$*\"\ndo\n    echo \"$var\"\ndone\n\necho \"print each param from \\\"\\$@\\\"\"\nfor var in \"$@\"\ndo\n    echo \"$var\"\ndone\n\n#-------\n# \u6267\u884c\u547d\u4ee4sh .\/test.sh a b c d\n# \u8f93\u51fa\u7ed3\u679c\n# print each param from \"$*\"\n# a b c d\n# print each param from \"$@\"\n# a\n# b\n# c\n# d\n#-------<\/code><\/pre>\n\n\n\n<p>\u9000\u51fa\u72b6\u6001<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>$?<\/code> \u53ef\u4ee5\u83b7\u53d6\u4e0a\u4e00\u4e2a\u547d\u4ee4\u7684\u9000\u51fa\u72b6\u6001\u3002\u6240\u8c13\u9000\u51fa\u72b6\u6001\uff0c\u5c31\u662f\u4e0a\u4e00\u4e2a\u547d\u4ee4\u6267\u884c\u540e\u7684\u8fd4\u56de\u7ed3\u679c<\/li>\n\n\n\n<li>\u9000\u51fa\u72b6\u6001\u662f\u4e00\u4e2a\u6570\u5b57\uff0c\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u5927\u90e8\u5206\u547d\u4ee4\u6267\u884c\u6210\u529f\u4f1a\u8fd4\u56de 0\uff0c\u5931\u8d25\u8fd4\u56de 1\uff1b\u4e0d\u8fc7\uff0c\u4e5f\u6709\u4e00\u4e9b\u547d\u4ee4\u8fd4\u56de\u5176\u4ed6\u503c\uff0c\u8868\u793a\u4e0d\u540c\u7c7b\u578b\u7684\u9519\u8bef\u3002<\/li>\n\n\n\n<li>\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  if &#91;&#91; $? != 0 ]];then\n      echo \"error\"\n      exit 1;\n  fi<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2.6 \u53d8\u91cf\u68c0\u6d4b\u8bed\u53e5<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u5f62\u5f0f<\/th><th>\u8bf4\u660e<\/th><\/tr><\/thead><tbody><tr><td><code>${var}<\/code><\/td><td>\u53d8\u91cf\u672c\u6765\u7684\u503c<\/td><\/tr><tr><td><code>${var:-word}<\/code><\/td><td>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u4e3a\u7a7a\u6216\u5df2\u88ab\u5220\u9664(unset)\uff0c\u90a3\u4e48\u8fd4\u56de word\uff0c\u4f46\u4e0d\u6539\u53d8 <code>var<\/code> \u7684\u503c\u3002<\/td><\/tr><tr><td><code>${var:=word}<\/code><\/td><td>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u4e3a\u7a7a\u6216\u5df2\u88ab\u5220\u9664(unset)\uff0c\u90a3\u4e48\u8fd4\u56de word\uff0c\u5e76\u5c06 <code>var<\/code> \u7684\u503c\u8bbe\u7f6e\u4e3a word\u3002<\/td><\/tr><tr><td><code>${var:?message}<\/code><\/td><td>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u4e3a\u7a7a\u6216\u5df2\u88ab\u5220\u9664(unset)\uff0c\u90a3\u4e48\u5c06\u6d88\u606f message \u9001\u5230\u6807\u51c6\u9519\u8bef\u8f93\u51fa\uff0c\u53ef\u4ee5\u7528\u6765\u68c0\u6d4b\u53d8\u91cf <code>var<\/code> \u662f\u5426\u53ef\u4ee5\u88ab\u6b63\u5e38\u8d4b\u503c\u3002\u82e5\u6b64\u66ff\u6362\u51fa\u73b0\u5728Shell\u811a\u672c\u4e2d\uff0c\u90a3\u4e48\u811a\u672c\u5c06\u505c\u6b62\u8fd0\u884c\u3002<\/td><\/tr><tr><td><code>${var:+word}<\/code><\/td><td>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u88ab\u5b9a\u4e49\uff0c\u90a3\u4e48\u8fd4\u56de word\uff0c\u4f46\u4e0d\u6539\u53d8 var \u7684\u503c\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><code>${var}<\/code>\u8bed\u53e5<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53d8\u91cf\u672c\u6765\u7684\u503c<\/li>\n<\/ul>\n\n\n\n<p><code>${var:-word}<\/code>\u8bed\u53e5<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u4e3a\u7a7a\u6216\u5df2\u88ab\u5220\u9664\uff0c\u90a3\u4e48\u8fd4\u56de <code>word<\/code>\uff0c\u4f46\u4e0d\u6539\u53d8 <code>var<\/code> \u7684\u503c;\u5426\u5219\u8fd4\u56de<code>var<\/code>\u7684\u503c<\/li>\n\n\n\n<li>\u793a\u4f8b\uff1a <\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\n\nvar=\"var\"\nword=\"word\"\n\necho ${var:-word}            #var\nunset var\necho ${var:-word}            #word<\/code><\/pre>\n\n\n\n<p><code>${var:=word}<\/code>\u8bed\u53e5<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u4e3a\u7a7a\u6216\u5df2\u88ab\u5220\u9664\uff0c\u90a3\u4e48\u8fd4\u56de <code>word<\/code>\uff0c\u5e76\u5c06 <code>var<\/code> \u7684\u503c\u8bbe\u7f6e\u4e3a <code>word<\/code>\uff1b\u5426\u5219\u8fd4\u56de<code>var<\/code>\u7684\u503c<\/li>\n\n\n\n<li>\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  #!\/bin\/Bash\n\n  var=\"var\"\n  word=\"word\"\n\n  echo ${var:=word}              #word\n  echo $var                      #var\n  unset var\n  echo ${var:=word}              #var\n  echo $var                      #word<\/code><\/pre>\n\n\n\n<p><code>${var:?message}<\/code>\u8bed\u53e5<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u4e3a\u7a7a\u6216\u5df2\u88ab\u5220\u9664\uff0c\u90a3\u4e48\u5c06<code>message<\/code>\u53d1\u9001\u81f3\u6807\u51c6\u9519\u8bef\u8f93\u51fa \uff0c\u5426\u5219\u8fd4\u56de<code>var<\/code>\uff1b<\/li>\n\n\n\n<li>\u53ef\u4ee5\u7528\u6765\u68c0\u6d4b\u53d8\u91cf <code>var<\/code> \u662f\u5426\u53ef\u4ee5\u88ab\u6b63\u5e38\u8d4b\u503c\u3002<strong>\u82e5\u6b64\u66ff\u6362\u51fa\u73b0\u5728Shell\u811a\u672c\u4e2d\uff0c\u90a3\u4e48\u811a\u672c\u5c06\u505c\u6b62\u8fd0\u884c<\/strong><\/li>\n\n\n\n<li>\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  #!\/bin\/Bash\n\n  name=\"Alice\"\n  echo \"Hello, ${name:?Variable 'name' is not defined or empty!}\"  #Hello, Alice\n\n  unset name  # \u5220\u9664\u53d8\u91cfname\n  echo \"Hello, ${name:?Variable 'name' is not defined or empty!}\"  #Variable 'name' is not defined or empty!\n\n  echo \"Hello World\"              #\u4e0d\u6267\u884c<\/code><\/pre>\n\n\n\n<p><code>${var:+word}<\/code>\u8bed\u53e5<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u53d8\u91cf <code>var<\/code> \u88ab\u5b9a\u4e49\uff0c\u90a3\u4e48\u8fd4\u56de <code>word<\/code>\uff0c\u4f46\u4e0d\u6539\u53d8 <code>var<\/code> \u7684\u503c\uff1b\u5426\u5219\u8fd4\u56de\u7a7a<\/li>\n\n\n\n<li>\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  #!\/bin\/Bash\n\n  var=\"var\"\n  word=\"word\"\n\n  echo ${var:+word}                #word\n\n  unset var\n  echo ${var:+word}                #\u7a7a\u503c<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">3. \u5b57\u7b26\u4e32<\/h2>\n\n\n\n<p><code>Shell<\/code>\u7684\u5b57\u7b26\u4e32\u7531\u5355\u5f15\u53f7\u6216\u53cc\u5f15\u53f7\u5305\u88f9\uff1b\u4e24\u8005\u4e0d\u5b8c\u5168\u76f8\u540c<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3.1 \u5355\u53cc\u5f15\u53f7\u7684\u533a\u522b<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53cc\u5f15\u53f7\u91cc\u53ef\u4ee5\u6709\u53d8\u91cf\u6216\u8f6c\u4e49\u5b57\u7b26\uff0c<strong>\u5355\u5f15\u53f7\u91cc\u7684\u4efb\u4f55\u5b57\u7b26\u90fd\u4f1a\u539f\u6837\u8f93\u51fa<\/strong>\uff0c\u5355\u5f15\u53f7\u5b57\u7b26\u4e32\u4e2d\u7684\u53d8\u91cf\u662f\u65e0\u6548\u7684\uff1b<\/li>\n\n\n\n<li>\u5355\u5f15\u53f7\u5b57\u4e32\u4e2d\u4e0d\u80fd\u51fa\u73b0\u5355\u72ec\u4e00\u4e2a\u7684\u5355\u5f15\u53f7\uff08\u5bf9\u5355\u5f15\u53f7\u4f7f\u7528\u8f6c\u4e49\u7b26\u540e\u4e5f\u4e0d\u884c\uff09\uff0c\u4f46\u53ef\u6210\u5bf9\u51fa\u73b0\uff0c\u4f5c\u4e3a\u5b57\u7b26\u4e32\u62fc\u63a5\u4f7f\u7528<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">3.2 \u5b57\u7b26\u4e32\u622a\u53d6<\/h3>\n\n\n\n<p><strong><code>#<\/code>\u53f7\u622a\u53d6\uff0c\u5220\u9664\u5de6\u8fb9\u5b57\u7b26\uff0c\u4fdd\u7559\u53f3\u8fb9\u5b57\u7b26<\/strong><\/p>\n\n\n\n<p>\u5176\u4e2d <code>var<\/code> \u662f\u53d8\u91cf\u540d\uff0c<code>#<\/code> \u53f7\u662f\u8fd0\u7b97\u7b26\uff0c<code>*\/\/<\/code> \u8868\u793a\u4ece\u5de6\u8fb9\u5f00\u59cb\u5220\u9664\u7b2c\u4e00\u4e2a <code>\/\/<\/code> \u53f7\u53ca\u5de6\u8fb9\u7684\u6240\u6709\u5b57\u7b26<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n# \u5373\u5220\u9664 'http:\/\/'\necho ${var#*\/\/}                         #www.aaa.com\/123.htm<\/code><\/pre>\n\n\n\n<p><strong><code>##<\/code>\u53f7\u622a\u53d6\uff0c\u5220\u9664\u5de6\u8fb9\u5b57\u7b26\uff0c\u4fdd\u7559\u53f3\u8fb9\u5b57\u7b26<\/strong><\/p>\n\n\n\n<p><code>\\##*\/<\/code> \u8868\u793a\u4ece\u5de6\u8fb9\u5f00\u59cb\u5220\u9664\u6700\u540e\uff08\u6700\u53f3\u8fb9\uff09\u4e00\u4e2a <code>\/<\/code> \u53f7\u53ca\u5de6\u8fb9\u7684\u6240\u6709\u5b57\u7b26<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n# \u5220\u9664 'http:\/\/www.aaa.com\/'\necho ${var##*\/}                          #123.htm<\/code><\/pre>\n\n\n\n<p><strong><code>%<\/code>\u53f7\u622a\u53d6\uff0c\u5220\u9664\u53f3\u8fb9\u5b57\u7b26\uff0c\u4fdd\u7559\u5de6\u8fb9\u5b57\u7b26<\/strong><\/p>\n\n\n\n<p><code>%\/*<\/code> \u8868\u793a\u4ece\u53f3\u8fb9\u5f00\u59cb\uff0c\u5220\u9664\u7b2c\u4e00\u4e2a <code>\/<\/code> \u53f7\u53ca\u53f3\u8fb9\u7684\u5b57\u7b26<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n# \u5220\u9664 '\/123.htm'\necho ${var%\/*}                            #http:\/\/www.aaa.com<\/code><\/pre>\n\n\n\n<p><strong><code>%%<\/code> \u53f7\u622a\u53d6\uff0c\u5220\u9664\u53f3\u8fb9\u5b57\u7b26\uff0c\u4fdd\u7559\u5de6\u8fb9\u5b57\u7b26<\/strong><\/p>\n\n\n\n<p><code>%%\/*<\/code> \u8868\u793a\u4ece\u53f3\u8fb9\u5f00\u59cb\uff0c\u5220\u9664\u6700\u540e\uff08\u6700\u5de6\u8fb9\uff09\u4e00\u4e2a <code>\/<\/code> \u53f7\u53ca\u53f3\u8fb9\u7684\u5b57\u7b26<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n# \u5220\u9664'http:\/\/www.aaa.com'\necho ${var%%\/*}                          #http:<\/code><\/pre>\n\n\n\n<p><strong>\u4ece\u5de6\u8fb9\u7b2c\u51e0\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c\u53ca\u5b57\u7b26\u7684\u4e2a\u6570<\/strong><\/p>\n\n\n\n<p>\u5176\u4e2d\u7684 <code>0<\/code> \u8868\u793a\u5de6\u8fb9\u7b2c\u4e00\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c<code>5<\/code> \u8868\u793a\u5de6\u8fb9\u7b2c\u4e94\u4e2a\u5b57\u7b26\u7ed3\u675f<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n#\u622a\u53d6\u7b2c1\u5230\u7b2c5\u4e2a\u5b57\u7b26\necho ${var:0:5}                         #http:<\/code><\/pre>\n\n\n\n<p><strong>\u4ece\u5de6\u8fb9\u7b2c\u51e0\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c\u4e00\u76f4\u5230\u7ed3\u675f<\/strong><\/p>\n\n\n\n<p>\u5176\u4e2d\u7684 <strong><code>7<\/code> \u8868\u793a\u5de6\u8fb9\u7b2c<code>8<\/code>\u4e2a\u5b57\u7b26\u5f00\u59cb<\/strong>\uff0c\u4e00\u76f4\u5230\u7ed3\u675f<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n#\u622a\u53d6\u7b2c8\u5230\u7ed3\u675f\u7684\u5b57\u7b26\u4e32\necho ${var:7}                           #www.aaa.com\/123.htm<\/code><\/pre>\n\n\n\n<p><strong>\u4ece\u53f3\u8fb9\u7b2c\u51e0\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c\u53ca\u5b57\u7b26\u7684\u4e2a\u6570<\/strong><\/p>\n\n\n\n<p>\u5176\u4e2d\u7684 <code>0-7<\/code> \u8868\u793a\u53f3\u8fb9\u7b97\u8d77\u7b2c\u4e03\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c<code>3<\/code> \u8868\u793a\u5b57\u7b26\u7684\u4e2a\u6570<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n#\u622a\u53d6\u4ece\u540e\u5411\u524d\u7684\u4e03\u4e2a\u5b57\u7b26\u4e2d\u7684\u524d\u4e09\u4e2a\necho ${var:0-7:3}                           #123<\/code><\/pre>\n\n\n\n<p><strong>\u4ece\u53f3\u8fb9\u7b2c\u51e0\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c\u4e00\u76f4\u5230\u7ed3\u675f<\/strong><\/p>\n\n\n\n<p>\u8868\u793a\u4ece\u53f3\u8fb9\u7b2c\u4e03\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c\u4e00\u76f4\u5230\u7ed3\u675f<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var=http:\/\/www.aaa.com\/123.htm\n#\u622a\u53d6\u4ece\u540e\u5411\u524d\u7684\u4e03\u4e2a\u5b57\u7b26\necho ${var:0-7}                           #123.html<\/code><\/pre>\n\n\n\n<p><strong>\u6ce8\uff1a<\/strong>\uff08\u5de6\u8fb9\u7684\u7b2c\u4e00\u4e2a\u5b57\u7b26\u662f\u7528 <code>0<\/code> \u8868\u793a\uff0c\u53f3\u8fb9\u7684\u7b2c\u4e00\u4e2a\u5b57\u7b26\u7528 <code>0-1<\/code> \u8868\u793a\uff09<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">4. \u6570\u7ec4<\/h2>\n\n\n\n<p><code>Bash<\/code>\u652f\u6301\u4e00\u7ef4\u6570\u7ec4\uff08\u4e0d\u652f\u6301\u591a\u7ef4\u6570\u7ec4\uff09\uff0c\u5e76\u4e14\u6ca1\u6709\u9650\u5b9a\u6570\u7ec4\u7684\u5927\u5c0f\u3002\u7c7b\u4f3c\u4e0e<code>C<\/code>\u8bed\u8a00\uff0c\u6570\u7ec4\u5143\u7d20\u7684\u4e0b\u6807\u7531<code>0<\/code>\u5f00\u59cb\u7f16\u53f7\u3002\u83b7\u53d6\u6570\u7ec4\u4e2d\u7684\u5143\u7d20\u8981\u5229\u7528\u4e0b\u6807\uff0c\u4e0b\u6807\u53ef\u4ee5\u662f\u6574\u6570\u6216\u7b97\u672f\u8868\u8fbe\u5f0f\uff0c\u5176\u503c\u5e94\u5927\u4e8e\u6216\u7b49\u4e8e<code>0<\/code>\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4.1 \u6570\u7ec4\u8d4b\u503c<\/h3>\n\n\n\n<p>\u5728<code>Shell<\/code>\u4e2d\uff0c\u7528\u62ec\u53f7\u6765\u8868\u793a\u6570\u7ec4\uff0c\u6570\u7ec4\u5143\u7d20\u7528<code>\u7a7a\u683c<\/code>\u7b26\u53f7\u5206\u5272\u5f00\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code># \u98ce\u683c1\narray_name=(value0 value1 value2 value3)\n\n# \u98ce\u683c2\narray_name=(\n    value0\n    value1\n    value2\n    value3\n)<\/code><\/pre>\n\n\n\n<p>\u8fd8\u53ef\u4ee5\u5355\u72ec\u5b9a\u4e49\u6570\u7ec4\u7684\u5404\u4e2a\u5206\u91cf\uff1a<\/p>\n\n\n\n<p>\u4ee5\u4e0d\u4f7f\u7528\u8fde\u7eed\u7684\u4e0b\u6807\uff0c\u800c\u4e14\u4e0b\u6807\u7684\u8303\u56f4\u6ca1\u6709\u9650\u5236<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>array_name&#91;0]=value0\narray_name&#91;1]=value1\narray_name&#91;2]=value2<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">4.2 \u6570\u7ec4\u6253\u5370<\/h3>\n\n\n\n<p><code>Shell<\/code>\u4e2d\u6709\u51e0\u79cd\u65b9\u5f0f\u53ef\u4ee5\u6253\u5370\u6570\u7ec4<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>echo ${array_name&#91;2]} #\u8bfb\u53d6\u4e0b\u6807\u4e3a2\u7684\u5143\u7d20\necho ${array_name&#91;*]} #\u8bfb\u53d6\u6240\u6709\u5143\u7d20\necho ${array_name&#91;@]} #\u8bfb\u53d6\u6240\u6709\u5143\u7d20\n\necho ${#array_name&#91;*]} #\u83b7\u53d6\u6570\u7ec4\u957f\u5ea6\necho ${#array_name&#91;@]} #\u83b7\u53d6\u6570\u7ec4\u957f\u5ea6\necho ${#array_name&#91;1]} #\u83b7\u53d6\u6570\u7ec4\u4e2d\u5355\u4e2a\u5143\u7d20\u7684\u957f\u5ea6\n\n# \u4ee5\u4e0a\u8ff0\u5b9a\u4e49\u7684\u6570\u7ec4\u4e3a\u4f8b\uff0c\u8f93\u51fa\u7ed3\u679c\n# value2\n# value0 value1 value2 value3\n# value0 value1 value2 value3\n# 4\n# 4\n# 6<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">5. \u8fd0\u7b97\u7b26<\/h2>\n\n\n\n<p><code>Bash<\/code> \u652f\u6301\u5f88\u591a\u8fd0\u7b97\u7b26\uff0c\u5305\u62ec\u7b97\u6570\u8fd0\u7b97\u7b26\u3001\u5173\u7cfb\u8fd0\u7b97\u7b26\u3001\u5e03\u5c14\u8fd0\u7b97\u7b26\u3001\u5b57\u7b26\u4e32\u8fd0\u7b97\u7b26\u548c\u6587\u4ef6\u6d4b\u8bd5\u8fd0\u7b97\u7b26<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5.1 \u7b97\u672f\u8fd0\u7b97\u7b26<\/h3>\n\n\n\n<p>\u539f\u751f<code>Bash<\/code>\u4e0d\u652f\u6301\u7b80\u5355\u7684\u6570\u5b66\u8fd0\u7b97\uff0c\u4f46\u662f\u53ef\u4ee5\u901a\u8fc7\u5176\u4ed6\u547d\u4ee4\u6765\u5b9e\u73b0\uff0c\u4f8b\u5982 <code>awk<\/code> \u548c <code>expr<\/code>\uff0c<code>expr<\/code> \u6700\u5e38\u7528<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>expr<\/code> \u662f\u4e00\u6b3e\u8868\u8fbe\u5f0f\u8ba1\u7b97\u5de5\u5177\uff0c\u4f7f\u7528\u5b83\u80fd\u5b8c\u6210\u8868\u8fbe\u5f0f\u7684\u6c42\u503c\u64cd\u4f5c\u3002<\/li>\n\n\n\n<li>\u4f8b\u5982\uff0c\u4e24\u4e2a\u6570\u76f8\u52a0\u4f7f\u7528\u53cd\u5f15\u53f7(<strong>\u6ce8\u610f\u4f7f\u7528\u7684\u662f\u53cd\u5f15\u53f7` \u800c\u4e0d\u662f\u5355\u5f15\u53f7&#8217;<\/strong>)\uff1a\u6216\u8005<strong>$()<\/strong>\u7b26\u53f7 <code>#!\/bin\/Bash val=`expr 2 + 2` echo \"\u4e24\u6570\u4e4b\u548c\u4e3a : $val\"<\/code><\/li>\n\n\n\n<li>\u8868\u8fbe\u5f0f\u548c\u8fd0\u7b97\u7b26\u4e4b\u95f4\u8981\u6709\u7a7a\u683c\uff0c\u4f8b\u5982 <code>2+2<\/code> \u662f\u4e0d\u5bf9\u7684\uff0c\u5fc5\u987b\u5199\u6210 <code>2 + 2<\/code>\uff0c\u8fd9\u4e0e\u6211\u4eec\u719f\u6089\u7684\u5927\u591a\u6570\u7f16\u7a0b\u8bed\u8a00\u4e0d\u4e00\u6837\u3002<\/li>\n\n\n\n<li>\u5b8c\u6574\u7684\u8868\u8fbe\u5f0f\u8981\u88ab `\u5305\u542b<\/li>\n\n\n\n<li>\u53ef\u4ee5\u4f7f\u7528\u5176\u4ed6\u7684\u7684\u8fd0\u7b97\u7b26\u8fdb\u884c\u8ba1\u7b97<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\n\na=10\nb=20\n\n# \u4e58\u53f7(*)\u524d\u8fb9\u5fc5\u987b\u52a0\u53cd\u659c\u6760(\\)\u624d\u80fd\u5b9e\u73b0\u4e58\u6cd5\u8fd0\u7b97\nval=`expr $a \\* $b`\necho \"a * b : $val\"<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">5.2 \u5173\u7cfb\u8fd0\u7b97\u7b26<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5173\u7cfb\u8fd0\u7b97\u7b26\u53ea\u652f\u6301\u6570\u5b57\uff0c\u4e0d\u652f\u6301\u5b57\u7b26\u4e32\uff0c\u9664\u975e\u5b57\u7b26\u4e32\u7684\u503c\u662f\u6570\u5b57<\/li>\n\n\n\n<li>\u5173\u7cfb\u8fd0\u7b97\u8bed\u53e5\u9700\u8981\u5728<code>[]<\/code>\u7b26\u53f7\u4e2d<\/li>\n<\/ul>\n\n\n\n<p>\u5e38\u89c1\u5173\u7cfb\u8fd0\u7b97\u7b26<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u8fd0\u7b97\u7b26<\/th><th>\u8bf4\u660e<\/th><th>\u4e3e\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>-eq<\/td><td>\u68c0\u6d4b\u4e24\u4e2a\u6570\u662f\u5426\u76f8\u7b49\uff0c\u76f8\u7b49\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -eq <code>$b<\/code> ] \u8fd4\u56de false<\/td><\/tr><tr><td>-ne<\/td><td>\u68c0\u6d4b\u4e24\u4e2a\u6570\u662f\u5426\u4e0d\u76f8\u7b49\uff0c\u4e0d\u76f8\u7b49\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -ne <code>$b<\/code> ] \u8fd4\u56de true<\/td><\/tr><tr><td>-gt<\/td><td>\u68c0\u6d4b\u5de6\u8fb9\u7684\u6570\u662f\u5426\u5927\u4e8e\u53f3\u8fb9\u7684\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -gt <code>$b<\/code> ] \u8fd4\u56de false<\/td><\/tr><tr><td>-lt<\/td><td>\u68c0\u6d4b\u5de6\u8fb9\u7684\u6570\u662f\u5426\u5c0f\u4e8e\u53f3\u8fb9\u7684\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -lt <code>$b<\/code> ] \u8fd4\u56de true<\/td><\/tr><tr><td>-ge<\/td><td>\u68c0\u6d4b\u5de6\u8fb9\u7684\u6570\u662f\u5426\u5927\u4e8e\u7b49\u4e8e\u53f3\u8fb9\u7684\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -ge <code>$b<\/code> ] \u8fd4\u56de false<\/td><\/tr><tr><td>-le<\/td><td>\u68c0\u6d4b\u5de6\u8fb9\u7684\u6570\u662f\u5426\u5c0f\u4e8e\u7b49\u4e8e\u53f3\u8fb9\u7684\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -le <code>$b<\/code> ] \u8fd4\u56de true<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if &#91; $a -eq $b ]\nthen\n    echo \"$a -eq $b : a \u7b49\u4e8e b\"\nelse\n    echo \"$a -eq $b: a \u4e0d\u7b49\u4e8e b\"\nfi<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">5.3 \u5e03\u5c14\u8fd0\u7b97\u7b26<\/h3>\n\n\n\n<p>\u5e38\u89c1\u5e03\u5c14\u8fd0\u7b97\u7b26<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u8fd0\u7b97\u7b26<\/th><th>\u8bf4\u660e<\/th><th>\u4e3e\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>!<\/td><td>\u975e\u8fd0\u7b97\uff0c\u8868\u8fbe\u5f0f\u4e3a true \u5219\u8fd4\u56de false\uff0c\u5426\u5219\u8fd4\u56de true<\/td><td>[ ! false ] \u8fd4\u56de true<\/td><\/tr><tr><td>-o<\/td><td>\u6216\u8fd0\u7b97\uff0c\u6709\u4e00\u4e2a\u8868\u8fbe\u5f0f\u4e3a true \u5219\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -lt 20 -o <code>$b<\/code> -gt 100 ] \u8fd4\u56de true<\/td><\/tr><tr><td>-a<\/td><td>\u4e0e\u8fd0\u7b97\uff0c\u4e24\u4e2a\u8868\u8fbe\u5f0f\u90fd\u4e3a true \u624d\u8fd4\u56de true<\/td><td>[ <code>$a<\/code> -lt 20 -a <code>$b<\/code> -gt 100 ] \u8fd4\u56de false<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">5.4 \u903b\u8f91\u8fd0\u7b97\u7b26<\/h3>\n\n\n\n<p>\u4f7f\u7528 <strong><code>[[ ... ]]<\/code><\/strong> \u6761\u4ef6\u5224\u65ad\u7ed3\u6784\uff0c\u800c\u4e0d\u662f <strong><code>[ ... ]<\/code><\/strong>\uff0c\u80fd\u591f\u9632\u6b62\u811a\u672c\u4e2d\u7684\u8bb8\u591a\u903b\u8f91\u9519\u8bef\u3002\u6bd4\u5982\uff0c<strong><code>&amp;&amp;<\/code><\/strong>\u3001<strong><code>||<\/code><\/strong>\u3001<strong><code>&lt;<\/code><\/strong> \u548c <strong><code>&gt;<\/code><\/strong> \u64cd\u4f5c\u7b26\u80fd\u591f\u6b63\u5e38\u5b58\u5728\u4e8e <strong><code>[[ ]]<\/code><\/strong> \u6761\u4ef6\u5224\u65ad\u7ed3\u6784\u4e2d\uff0c\u4f46\u662f\u5982\u679c\u51fa\u73b0\u5728 <strong><code>[ ]<\/code><\/strong> \u7ed3\u6784\u4e2d\u7684\u8bdd\uff0c\u4f1a\u62a5\u9519<\/p>\n\n\n\n<p>\u5e38\u89c1\u903b\u8f91\u8fd0\u7b97\u7b26<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u8fd0\u7b97\u7b26<\/th><th>\u8bf4\u660e<\/th><th>\u4e3e\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>&amp;&amp;<\/td><td>\u903b\u8f91\u7684 AND<\/td><td>[[ <code>$a<\/code> -lt 100 &amp;&amp; <code>$b<\/code> -gt 100 ]] \u8fd4\u56de false<\/td><\/tr><tr><td>||<\/td><td>\u903b\u8f91\u7684 OR<\/td><td>[[ <code>$a<\/code> -lt 100 || <code>$b<\/code> -gt 100 ]] \u8fd4\u56de true<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">5.5 \u5b57\u7b26\u4e32\u8fd0\u7b97\u7b26<\/h3>\n\n\n\n<p>\u5e38\u89c1\u5b57\u7b26\u4e32\u8fd0\u7b97\u7b26<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u8fd0\u7b97\u7b26<\/th><th>\u8bf4\u660e<\/th><th>\u4e3e\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>=<\/td><td>\u68c0\u6d4b\u4e24\u4e2a\u5b57\u7b26\u4e32\u662f\u5426\u76f8\u7b49\uff0c\u76f8\u7b49\u8fd4\u56de true\u3002<\/td><td>[ <code>$a<\/code> = <code>$b<\/code> ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>!=<\/td><td>\u68c0\u6d4b\u4e24\u4e2a\u5b57\u7b26\u4e32\u662f\u5426\u4e0d\u76f8\u7b49\uff0c\u4e0d\u76f8\u7b49\u8fd4\u56de true\u3002<\/td><td>[ <code>$a<\/code> != <code>$b<\/code> ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>-z<\/td><td>\u68c0\u6d4b\u5b57\u7b26\u4e32\u957f\u5ea6\u662f\u5426\u4e3a0\uff0c\u4e3a0\u8fd4\u56de true\u3002<\/td><td>[ -z <code>$a<\/code> ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>-n<\/td><td>\u68c0\u6d4b\u5b57\u7b26\u4e32\u957f\u5ea6\u662f\u5426\u4e0d\u4e3a 0\uff0c\u4e0d\u4e3a 0 \u8fd4\u56de true\u3002<\/td><td>[ -n &#8220;<code>$a<\/code>&#8221; ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>$<\/td><td>\u68c0\u6d4b\u5b57\u7b26\u4e32\u662f\u5426\u4e0d\u4e3a\u7a7a\uff0c\u4e0d\u4e3a\u7a7a\u8fd4\u56de true\u3002<\/td><td>[ <code>$a<\/code> ] \u8fd4\u56de true\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u5b9e\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\n\n# \u6b63\u786e\u7684\u505a\u6cd5\u662f $a \u8fd9\u91cc\u5e94\u8be5\u52a0\u4e0a\u53cc\u5f15\u53f7\uff0c\u5426\u5219 -n $a \u7684\u7ed3\u679c\u6c38\u8fdc\u662f true\uff1a\na=\"\"\nif &#91; -n \"$a\" ]\nthen\n   echo \"-n $a : \u5b57\u7b26\u4e32\u957f\u5ea6\u4e0d\u4e3a 0\"\nelse\n   echo \"-n $a : \u5b57\u7b26\u4e32\u957f\u5ea6\u4e3a 0\"\nfi<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">5.6 \u6587\u4ef6\u6d4b\u8bd5\u8fd0\u7b97\u7b26<\/h3>\n\n\n\n<p>\u6587\u4ef6\u6d4b\u8bd5\u8fd0\u7b97\u7b26\u7528\u4e8e\u68c0\u6d4b <code>Unix<\/code> \u6587\u4ef6\u7684\u5404\u79cd\u5c5e\u6027<\/p>\n\n\n\n<p>\u5e38\u89c1\u6587\u4ef6\u6d4b\u8bd5\u8fd0\u7b97\u7b26<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u64cd\u4f5c\u7b26<\/th><th>\u8bf4\u660e<\/th><th>\u4e3e\u4f8b<\/th><\/tr><\/thead><tbody><tr><td>-b file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u662f\u5757\u8bbe\u5907\u6587\u4ef6\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -b $file ] \u8fd4\u56de false\u3002<\/td><\/tr><tr><td>-c file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u662f\u5b57\u7b26\u8bbe\u5907\u6587\u4ef6\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -c $file ] \u8fd4\u56de false\u3002<\/td><\/tr><tr><td>-d file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u662f\u76ee\u5f55\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -d $file ] \u8fd4\u56de false\u3002<\/td><\/tr><tr><td>-f file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u662f\u666e\u901a\u6587\u4ef6\uff08\u65e2\u4e0d\u662f\u76ee\u5f55\uff0c\u4e5f\u4e0d\u662f\u8bbe\u5907\u6587\u4ef6\uff09\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -f $file ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>-g file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u8bbe\u7f6e\u4e86 SGID \u4f4d\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -g $file ] \u8fd4\u56de false\u3002<\/td><\/tr><tr><td>-k file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u8bbe\u7f6e\u4e86\u7c98\u7740\u4f4d(Sticky Bit)\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -k $file ] \u8fd4\u56de false\u3002<\/td><\/tr><tr><td>-p file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u662f\u6709\u540d\u7ba1\u9053\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -p $file ] \u8fd4\u56de false\u3002<\/td><\/tr><tr><td>-u file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u8bbe\u7f6e\u4e86 SUID \u4f4d\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -u $file ] \u8fd4\u56de false\u3002<\/td><\/tr><tr><td>-r file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u53ef\u8bfb\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -r $file ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>-w file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u53ef\u5199\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -w $file ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>-x file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u53ef\u6267\u884c\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -x $file ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>-s file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\u662f\u5426\u4e3a\u7a7a\uff08\u6587\u4ef6\u5927\u5c0f\u662f\u5426\u5927\u4e8e0\uff09\uff0c\u4e0d\u4e3a\u7a7a\u8fd4\u56de true\u3002<\/td><td>[ -s $file ] \u8fd4\u56de true\u3002<\/td><\/tr><tr><td>-e file<\/td><td>\u68c0\u6d4b\u6587\u4ef6\uff08\u5305\u62ec\u76ee\u5f55\uff09\u662f\u5426\u5b58\u5728\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de true\u3002<\/td><td>[ -e $file ] \u8fd4\u56de true\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u5b9e\u4f8b:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\n\nfile=\"\/var\/test.sh\"\nif &#91; -r $file ]\nthen\n   echo \"\u6587\u4ef6\u53ef\u8bfb\"\nelse\n   echo \"\u6587\u4ef6\u4e0d\u53ef\u8bfb\"\nfi<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">6. \u7279\u6b8a\u7b26\u53f7<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">6.1 <code>[]<\/code>\u7b26\u53f7<\/h3>\n\n\n\n<p>\u5728Shell\u4e2d\uff0c<code>[]<\/code> \u662f\u4e00\u79cd\u7528\u4e8e\u6761\u4ef6\u6d4b\u8bd5\u548c\u6bd4\u8f83\u7684\u7279\u6b8a\u7b26\u53f7\u3002\u5b83\u901a\u5e38\u7528\u4e8e\u63a7\u5236\u6d41\u7a0b\u8bed\u53e5\uff08\u5982 if-then\u3001while \u548c for \u5faa\u73af\uff09\u4e2d\uff0c<code>[]<\/code> \u4e2d\u7684\u6761\u4ef6\u548c\u64cd\u4f5c\u7b26\u4e4b\u95f4\u9700\u8981\u6709\u7a7a\u683c\uff0c<code>[]<\/code> \u53ef\u4ee5\u7528\u4e8e\u4ee5\u4e0b\u60c5\u5883\uff1a<\/p>\n\n\n\n<p>\u6761\u4ef6\u6d4b\u8bd5\uff1a<code>[ condition ]<\/code> \u7528\u4e8e\u68c0\u67e5\u6761\u4ef6\u662f\u5426\u4e3a\u771f\u3002\u6761\u4ef6\u53ef\u4ee5\u662f\u53d8\u91cf\u3001\u6bd4\u8f83\u64cd\u4f5c\u7b26\u548c\u903b\u8f91\u64cd\u4f5c\u7b26\u7684\u7ec4\u5408\u3002\u5982\u679c\u6761\u4ef6\u4e3a\u771f\uff0c\u8fd4\u56de\u9000\u51fa\u7801 0\uff1b\u5982\u679c\u6761\u4ef6\u4e3a\u5047\uff0c\u8fd4\u56de\u975e\u96f6\u9000\u51fa\u7801\u3002<\/p>\n\n\n\n<p><strong>\u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if &#91; $count -gt 10 ]; \n    then echo \"count is greater than 10\"; \nfi<\/code><\/pre>\n\n\n\n<p>\u5b57\u7b26\u4e32\u6bd4\u8f83\uff1a<code>[ string1 = string2 ]<\/code> \u7528\u4e8e\u6bd4\u8f83\u4e24\u4e2a\u5b57\u7b26\u4e32\u662f\u5426\u76f8\u7b49\u3002\u5176\u4ed6\u5b57\u7b26\u4e32\u6bd4\u8f83\u64cd\u4f5c\u7b26\u8fd8\u5305\u62ec<code>!=<\/code>\uff08\u4e0d\u76f8\u7b49\uff09\u3001<code>-z<\/code>\uff08\u7a7a\u5b57\u7b26\u4e32\uff09\u3001<code>-n<\/code>\uff08\u975e\u7a7a\u5b57\u7b26\u4e32\uff09\u7b49\u3002<\/p>\n\n\n\n<p><strong>\u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if &#91; \"$name\" = \"John\" ]; \n    then echo \"Hello, John!\"; \nfi<\/code><\/pre>\n\n\n\n<p>\u6570\u503c\u6bd4\u8f83\uff1a<code>[ num1 -eq num2 ]<\/code> \u7528\u4e8e\u6bd4\u8f83\u4e24\u4e2a\u6570\u503c\u662f\u5426\u76f8\u7b49\u3002\u5176\u4ed6\u6570\u503c\u6bd4\u8f83\u64cd\u4f5c\u7b26\u8fd8\u5305\u62ec<code>-ne<\/code>\uff08\u4e0d\u76f8\u7b49\uff09\u3001<code>-lt<\/code>\uff08\u5c0f\u4e8e\uff09\u3001<code>-gt<\/code>\uff08\u5927\u4e8e\uff09\u3001<code>-le<\/code>\uff08\u5c0f\u4e8e\u7b49\u4e8e\uff09\u3001<code>-ge<\/code>\uff08\u5927\u4e8e\u7b49\u4e8e\uff09\u7b49\u3002<\/p>\n\n\n\n<p><strong>\u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if &#91; $age -ge 18 ]; \n    then echo \"You are an adult.\"; \nfi<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">6.2 <code>[[]]<\/code>\u7b26\u53f7<\/h3>\n\n\n\n<p>\u5728<code>Shell<\/code>\u4e2d\uff0c<code>[[]]<\/code> \u662f\u4e00\u79cd\u6269\u5c55\u7684\u6761\u4ef6\u6d4b\u8bd5\u7ed3\u6784\uff0c\u901a\u5e38\u7528\u4e8e\u590d\u6742\u7684\u6761\u4ef6\u8868\u8fbe\u5f0f\u548c\u6a21\u5f0f\u5339\u914d\u3002\u76f8\u6bd4\u4e8e\u4f20\u7edf\u7684<code>[]<\/code>\uff0c<code>[[]]<\/code> \u63d0\u4f9b\u4e86\u66f4\u591a\u7684\u529f\u80fd\u548c\u66f4\u7075\u6d3b\u7684\u8bed\u6cd5<\/p>\n\n\n\n<p><code>[]<\/code>\u7b26\u53f7\u4e0e<code>[[]]<\/code>\u7b26\u53f7\u4e4b\u95f4\u5b58\u5728\u4e00\u4e9b\u533a\u522b<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><code>[ ]<\/code>\u662f\u7b26\u5408<code>POSIX<\/code>\u6807\u51c6\u7684\u6d4b\u8bd5\u8bed\u53e5\uff0c\u517c\u5bb9\u6027\u66f4\u5f3a\uff0c\u51e0\u4e4e\u53ef\u4ee5\u8fd0\u884c\u5728\u6240\u6709\u7684<code>Shell<\/code>\u89e3\u91ca\u5668\u4e2d\uff0c<code>[[ ]]<\/code>\u4ec5\u53ef\u8fd0\u884c\u5728\u7279\u5b9a\u7684\u51e0\u4e2aShell\u89e3\u91ca\u5668\u4e2d(\u5982<code>Bash<\/code>\u7b49)<\/li>\n\n\n\n<li><code>&lt;<\/code>\u548c<code>&gt;<\/code>\u5728<code>[[ ]]<\/code>\u4e2d\u7528\u4f5c\u6392\u5e8f\uff0c\u800c<code>[ ]<\/code>\u4e0d\u652f\u6301<\/li>\n\n\n\n<li><code>[ ]<\/code>\u4e2d\u4f7f\u7528<code>-a<\/code>\u548c<code>-o<\/code>\u8868\u793a\u903b\u8f91\u4e0e\u548c\u903b\u8f91\u6216\uff0c<code>[[ ]]<\/code>\u4f7f\u7528<code>&amp;&amp;<\/code>\u548c<code>||<\/code>\u6765\u8868\u793a<\/li>\n\n\n\n<li>\u6587\u4ef6\u540d\u6269\u5c55\uff1a<code>[[]]<\/code> \u652f\u6301\u4f7f\u7528 <code>*<\/code> \u548c <code>?<\/code> \u7b49\u901a\u914d\u7b26\u8fdb\u884c\u6587\u4ef6\u540d\u7684\u6269\u5c55\u5339\u914d\uff0c\u800c <code>[]<\/code> \u4e0d\u652f\u6301\u6587\u4ef6\u540d\u6269\u5c55<\/li>\n\n\n\n<li>\u6b63\u5219\u8868\u8fbe\u5f0f\u5339\u914d\uff1a<code>[[]]<\/code> \u652f\u6301\u4f7f\u7528 <code>=~<\/code> \u8fd0\u7b97\u7b26\u8fdb\u884c\u6b63\u5219\u8868\u8fbe\u5f0f\u7684\u5339\u914d\u5224\u65ad\uff0c\u800c <code>[]<\/code> \u4e0d\u652f\u6301\u76f4\u63a5\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u5339\u914d\uff0c\u9700\u8981\u501f\u52a9\u5176\u4ed6\u5de5\u5177\u6216\u547d\u4ee4\u6765\u5b9e\u73b0\u6b63\u5219\u5339\u914d<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">7. \u6761\u4ef6\u63a7\u5236<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">7.1 if\u8bed\u53e5<\/h3>\n\n\n\n<p>\u8bed\u6cd5\u683c\u5f0f\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if &#91; expression ]\nthen\n   Statement(s) to be executed if expression is true\nfi<\/code><\/pre>\n\n\n\n<p>\u6ce8\u610f\uff1a<code>expression<\/code> \u548c\u65b9\u62ec\u53f7<code>[ ]<\/code>\u4e4b\u95f4\u5fc5\u987b\u6709\u7a7a\u683c\uff0c\u5426\u5219\u4f1a\u6709\u8bed\u6cd5\u9519\u8bef\u3002<\/p>\n\n\n\n<p>\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if &#91; $a == $b ]\nthen \n    echo \"a is equal to b\"\nelse\n    echo \"a is less to b\"\nfi<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">7.2 case\u8bed\u53e5<\/h3>\n\n\n\n<p><code>case ... esac<\/code> \u4e0e\u5176\u4ed6\u8bed\u8a00\u4e2d\u7684 <code>switch ... case<\/code> \u8bed\u53e5\u7c7b\u4f3c\uff0c\u662f\u4e00\u79cd\u591a\u5206\u679d\u9009\u62e9\u7ed3\u6784<\/p>\n\n\n\n<p><strong>\u6ce8\u610f\uff1a<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53d6\u503c\u540e\u9762\u5fc5\u987b\u4e3a\u5173\u952e\u5b57 <code>in<\/code>\uff0c\u6bcf\u4e00\u6a21\u5f0f\u5fc5\u987b\u4ee5\u53f3\u62ec\u53f7\u7ed3\u675f\u3002\u53d6\u503c\u53ef\u4ee5\u4e3a\u53d8\u91cf\u6216\u5e38\u6570\u3002<\/li>\n\n\n\n<li>\u5339\u914d\u53d1\u73b0\u53d6\u503c\u7b26\u5408\u67d0\u4e00\u6a21\u5f0f\u540e\uff0c\u5176\u95f4\u6240\u6709\u547d\u4ee4\u5f00\u59cb\u6267\u884c\u76f4\u81f3 <code>;;<\/code>\u3002<code>;;<\/code> \u4e0e\u5176\u4ed6\u8bed\u8a00\u4e2d\u7684 <code>break<\/code> \u7c7b\u4f3c\uff0c\u610f\u601d\u662f\u8df3\u5230\u6574\u4e2a <code>case<\/code> \u8bed\u53e5\u7684\u6700\u540e\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>\u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>case $grade in \n    \"A\")\n        echo \"Very Good!\";;\n    \"B\")\n        echo \"Good!\";;\n    \"C\")\n        echo \"Come On!\";;\n    *)\n        echo \"You Must Try!\"\n        echo \"Sorry!\";;\nesac<\/code><\/pre>\n\n\n\n<p><strong>\u8f6c\u6362\u6210C\u8bed\u8a00\u662f\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>switch(grade){\n    case 'A': printf(\"Very Good!\");\n        break;\n    case 'B': printf(\"Very Good!\");\n        break;\n    case 'C': printf(\"Very Good!\");\n        break;\n    default: \n        printf(\"You Must Try!\");\n        printf(\"Sorry!\");\n        break;\n}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">7.3 for\u5faa\u73af<\/h3>\n\n\n\n<p>\u5f53\u53d8\u91cf\u503c\u5728\u5217\u8868\u91cc\uff0c<code>for<\/code> \u5faa\u73af\u5373\u6267\u884c\u4e00\u6b21\u6240\u6709\u547d\u4ee4\uff0c\u4f7f\u7528\u53d8\u91cf\u540d\u83b7\u53d6\u5217\u8868\u4e2d\u7684\u5f53\u524d\u53d6\u503c\u3002\u547d\u4ee4\u53ef\u4e3a\u4efb\u4f55\u6709\u6548\u7684 <code>Shell<\/code> \u547d\u4ee4\u548c\u8bed\u53e5\u3002\u5217\u8868\u53ef\u4ee5\u5305\u542b\u66ff\u6362\u3001\u5b57\u7b26\u4e32\u548c\u6587\u4ef6\u540d<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>for \u53d8\u91cf in \u5217\u8868\ndo\n    command1\n    command2\n    ...\n    commandN\ndone<\/code><\/pre>\n\n\n\n<p>\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\/\n\nfor value in 1 2 3 4 5\ndo \n    echo \"The value is $value\"\ndone\n\n# \u8f93\u51fa\n# The value is 1\n# The value is 2\n# The value is 3\n# The value is 4\n# The value is 5<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">7.4 while\u5faa\u73af<\/h3>\n\n\n\n<p>\u53ea\u8981while\u540e\u9762\u7684\u6761\u4ef6\u6ee1\u8db3\uff0c\u5c31\u4e00\u76f4\u6267\u884cdo\u91cc\u9762\u7684\u4ee3\u7801\u5757\u3002<\/p>\n\n\n\n<p>\u683c\u5f0f\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>while command\ndo\n   Statement(s) to be executed if command is true\ndone<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">7.5 until\u5faa\u73af<\/h3>\n\n\n\n<p><code>until<\/code>\u8bed\u53e5\u7c7b\u4f3c\u4e8e\u5176\u4ed6\u8bed\u8a00\u7684<code>do while<\/code>\u8bed\u53e5<\/p>\n\n\n\n<p><code>condition<\/code> \u4e00\u822c\u4e3a\u6761\u4ef6\u8868\u8fbe\u5f0f\uff0c\u5982\u679c\u8fd4\u56de\u503c\u4e3a <code>false<\/code>\uff0c\u5219\u7ee7\u7eed\u6267\u884c\u5faa\u73af\u4f53\u5185\u7684\u8bed\u53e5\uff0c\u5426\u5219\u8df3\u51fa\u5faa\u73af<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>until condition\ndo\n    command\ndone<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">7.6 \u8df3\u51fa\u5faa\u73af<\/h3>\n\n\n\n<p>\u5728\u5faa\u73af\u8fc7\u7a0b\u4e2d\uff0c\u6709\u65f6\u5019\u9700\u8981\u5728\u672a\u8fbe\u5230\u5faa\u73af\u7ed3\u675f\u6761\u4ef6\u65f6\u5f3a\u5236\u8df3\u51fa\u5faa\u73af\uff0c\u50cf\u5927\u591a\u6570\u7f16\u7a0b\u8bed\u8a00\u4e00\u6837\uff0c<code>Shell<\/code>\u4e5f\u4f7f\u7528 <code>break<\/code> \u548c <code>continue<\/code> \u6765\u8df3\u51fa\u5faa\u73af\u3002<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><code>break<\/code>\u8bed\u53e5<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>break<\/code> \u547d\u4ee4\u5141\u8bb8\u8df3\u51fa\u6240\u6709\u5faa\u73af\uff08\u7ec8\u6b62\u6267\u884c\u540e\u9762\u7684\u6240\u6709\u5faa\u73af\uff09<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><code>continue<\/code><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>continue<\/code>\u547d\u4ee4\u4e0e<code>break<\/code>\u547d\u4ee4\u7c7b\u4f3c\uff0c\u53ea\u6709\u4e00\u70b9\u5dee\u522b\uff0c\u5b83\u4e0d\u4f1a\u8df3\u51fa\u6240\u6709\u5faa\u73af\uff0c\u4ec5\u4ec5\u8df3\u51fa\u5f53\u524d\u5faa\u73af<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">8. \u51fd\u6570<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">8.1 \u51fd\u6570\u5b9a\u4e49<\/h3>\n\n\n\n<p><code>Shell<\/code> \u51fd\u6570\u7684\u5b9a\u4e49\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n\n\n\n<p>\u5176\u4e2d<code>function<\/code>\u5173\u952e\u5b57\u662f\u53ef\u9009\u7684\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function function_name () {\n    list of commands\n    &#91; return value ]\n}<\/code><\/pre>\n\n\n\n<p>\u51fd\u6570\u8fd4\u56de\u503c\uff0c\u53ef\u4ee5\u663e\u5f0f\u589e\u52a0return\u8bed\u53e5\uff1b\u5982\u679c\u4e0d\u52a0\uff0c\u4f1a\u5c06\u6700\u540e\u4e00\u6761\u547d\u4ee4\u8fd0\u884c\u7ed3\u679c\u4f5c\u4e3a\u8fd4\u56de\u503c<\/p>\n\n\n\n<p>\u50cf\u5220\u9664\u53d8\u91cf\u4e00\u6837\uff0c\u5220\u9664\u51fd\u6570\u4e5f\u53ef\u4ee5\u4f7f\u7528 <code>unset<\/code> \u547d\u4ee4\uff0c\u4e0d\u8fc7\u8981\u52a0\u4e0a <code>.f<\/code> \u9009\u9879\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>$unset .f function_name<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">8.2 \u51fd\u6570\u8c03\u7528<\/h3>\n\n\n\n<p>\u8c03\u7528\u51fd\u6570\u53ea\u9700\u8981\u7ed9\u51fa\u51fd\u6570\u540d\uff0c\u4e0d\u9700\u8981\u52a0\u62ec\u53f7<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">8.3 \u51fd\u6570\u53c2\u6570<\/h3>\n\n\n\n<p>\u5728Shell\u4e2d\uff0c\u8c03\u7528\u51fd\u6570\u65f6\u53ef\u4ee5\u5411\u5176\u4f20\u9012\u53c2\u6570\u3002\u5728\u51fd\u6570\u4f53\u5185\u90e8\uff0c\u901a\u8fc7 <code>$n<\/code> \u7684\u5f62\u5f0f\u6765\u83b7\u53d6\u53c2\u6570\u7684\u503c\uff0c\u4f8b\u5982\uff0c<code>$1<\/code>\u8868\u793a\u7b2c\u4e00\u4e2a\u53c2\u6570\uff0c<code>$2<\/code>\u8868\u793a\u7b2c\u4e8c\u4e2a\u53c2\u6570\u2026<\/p>\n\n\n\n<p>\u5e26\u53c2\u6570\u7684\u51fd\u6570\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#!\/bin\/Bash\n\nfunWithParam () {\n    echo \"\u7b2c\u4e00\u4e2a\u53c2\u6570\u4e3a $1 !\"\n    echo \"\u7b2c\u4e8c\u4e2a\u53c2\u6570\u4e3a $2 !\"\n    echo \"\u7b2c\u5341\u4e2a\u53c2\u6570\u4e3a $10 !\"\n    echo \"\u7b2c\u5341\u4e2a\u53c2\u6570\u4e3a ${10} !\"\n    echo \"\u53c2\u6570\u603b\u6570\u6709 $# \u4e2a!\"\n}\nfunWithParam 1 2 3 4 5 6 7 8 9 34 73\n\n# \u8f93\u51fa\n# \u7b2c\u4e00\u4e2a\u53c2\u6570\u4e3a 1 !\n# \u7b2c\u4e8c\u4e2a\u53c2\u6570\u4e3a 2 !\n# \u7b2c\u5341\u4e2a\u53c2\u6570\u4e3a 10 !\n# \u7b2c\u5341\u4e2a\u53c2\u6570\u4e3a 34 !\n# \u7b2c\u5341\u4e00\u4e2a\u53c2\u6570\u4e3a 73 !\n# \u53c2\u6570\u603b\u6570\u6709 11 \u4e2a!<\/code><\/pre>\n\n\n\n<p>\u6ce8\u610f\uff0c<code>$10<\/code> \u4e0d\u80fd\u83b7\u53d6\u7b2c\u5341\u4e2a\u53c2\u6570\uff0c\u83b7\u53d6\u7b2c\u5341\u4e2a\u53c2\u6570\u9700\u8981<code>${10}<\/code>\u3002\u5f53n&gt;=10\u65f6\uff0c\u9700\u8981\u4f7f\u7528<code>${n}<\/code>\u6765\u83b7\u53d6\u53c2\u6570<\/p>\n","protected":false},"excerpt":{"rendered":"<p>1. \u7b80\u4ecb 1.1 Shell \u73af\u5883 Shell \u7f16\u7a0b\u8ddf JavaScript\u3001php \u7f16\u7a0b\u4e00\u6837\uff0c\u53ea\u8981\u6709\u4e00\u4e2a\u80fd [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[7],"tags":[],"class_list":["post-329","post","type-post","status-publish","format-standard","hentry","category-learning-programming-languages"],"_links":{"self":[{"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=\/wp\/v2\/posts\/329","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=329"}],"version-history":[{"count":4,"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=\/wp\/v2\/posts\/329\/revisions"}],"predecessor-version":[{"id":335,"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=\/wp\/v2\/posts\/329\/revisions\/335"}],"wp:attachment":[{"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=329"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=329"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.garfield-blog.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=329"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}