{"id":210638,"date":"2023-12-22T07:08:17","date_gmt":"2023-12-21T23:08:17","guid":{"rendered":"https:\/\/www.idc.net\/help\/210638\/"},"modified":"2023-12-22T07:08:17","modified_gmt":"2023-12-21T23:08:17","slug":"linux-%e5%91%bd%e4%bb%a4%ef%bc%9aexpr-%e8%ae%a1%e7%ae%97%e8%a1%a8%e8%be%be%e5%bc%8f","status":"publish","type":"post","link":"https:\/\/idc.net\/help\/210638\/","title":{"rendered":"Linux \u547d\u4ee4\uff1aexpr &#8211; \u8ba1\u7b97\u8868\u8fbe\u5f0f"},"content":{"rendered":"<p><title id=\"linux-%e5%91%bd%e4%bb%a4%ef%bc%9aexpr-%e8%ae%a1%e7%ae%97%e8%a1%a8%e8%be%be%e5%bc%8f-iXEnEUkOmZ\">Linux \u547d\u4ee4\uff1aexpr - \u8ba1\u7b97\u8868\u8fbe\u5f0f<\/title><\/p>\n<h1 id=\"linux-%e5%91%bd%e4%bb%a4%ef%bc%9aexpr-%e8%ae%a1%e7%ae%97%e8%a1%a8%e8%be%be%e5%bc%8f-iXEnEUkOmZ\">Linux \u547d\u4ee4\uff1aexpr - \u8ba1\u7b97\u8868\u8fbe\u5f0f<\/h1>\n<p>\u5728Linux\u7cfb\u7edf\u4e2d\uff0cexpr\u547d\u4ee4\u662f\u4e00\u4e2a\u7528\u4e8e\u8ba1\u7b97\u8868\u8fbe\u5f0f\u7684\u5b9e\u7528\u5de5\u5177\u3002\u5b83\u53ef\u4ee5\u6267\u884c\u5404\u79cd\u6570\u5b66\u8fd0\u7b97\uff0c\u5305\u62ec\u52a0\u6cd5\u3001\u51cf\u6cd5\u3001\u4e58\u6cd5\u548c\u9664\u6cd5\uff0c\u8fd8\u53ef\u4ee5\u8fdb\u884c\u5b57\u7b26\u4e32\u6bd4\u8f83\u548c\u5339\u914d\u3002expr\u547d\u4ee4\u975e\u5e38\u7075\u6d3b\uff0c\u53ef\u4ee5\u7528\u4e8eshell\u811a\u672c\u548c\u547d\u4ee4\u884c\u64cd\u4f5c\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e8%af%ad%e6%b3%95-iXEnEUkOmZ\">\u57fa\u672c\u8bed\u6cd5<\/h2>\n<p>expr\u547d\u4ee4\u7684\u57fa\u672c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>expr EXPRESSION\n<\/code><\/pre>\n<p>\u5176\u4e2d\uff0cEXPRESSION\u662f\u8981\u8ba1\u7b97\u7684\u8868\u8fbe\u5f0f\u3002\u8868\u8fbe\u5f0f\u53ef\u4ee5\u5305\u542b\u6570\u5b57\u3001\u8fd0\u7b97\u7b26\u548c\u5b57\u7b26\u4e32\u3002<\/p>\n<h2 id=\"%e6%95%b0%e5%ad%a6%e8%bf%90%e7%ae%97-iXEnEUkOmZ\">\u6570\u5b66\u8fd0\u7b97<\/h2>\n<p>expr\u547d\u4ee4\u53ef\u4ee5\u6267\u884c\u5404\u79cd\u6570\u5b66\u8fd0\u7b97\uff0c\u5305\u62ec\u52a0\u6cd5\u3001\u51cf\u6cd5\u3001\u4e58\u6cd5\u548c\u9664\u6cd5\u3002\u4e0b\u9762\u662f\u4e00\u4e9b\u793a\u4f8b\uff1a<\/p>\n<pre><code>$ expr 5 + 3\n8\n\n$ expr 10 - 5\n5\n\n$ expr 2 * 3\n6\n\n$ expr 10 \/ 2\n5\n<\/code><\/pre>\n<p>\u5728\u8fdb\u884c\u4e58\u6cd5\u8fd0\u7b97\u65f6\uff0c\u9700\u8981\u4f7f\u7528\u53cd\u659c\u6760\uff08\uff09\u8f6c\u4e49\u4e58\u53f7\uff08*\uff09\uff0c\u4ee5\u9632\u6b62shell\u5c06\u5176\u89e3\u91ca\u4e3a\u901a\u914d\u7b26\u3002<\/p>\n<h2 id=\"%e5%ad%97%e7%ac%a6%e4%b8%b2%e6%af%94%e8%be%83-iXEnEUkOmZ\">\u5b57\u7b26\u4e32\u6bd4\u8f83<\/h2>\n<p>expr\u547d\u4ee4\u8fd8\u53ef\u4ee5\u7528\u4e8e\u5b57\u7b26\u4e32\u6bd4\u8f83\u548c\u5339\u914d\u3002\u4e0b\u9762\u662f\u4e00\u4e9b\u793a\u4f8b\uff1a<\/p>\n<pre><code>$ expr \"hello\" = \"hello\"\n1\n\n$ expr \"hello\" != \"world\"\n1\n\n$ expr \"hello\" : \"he.*\"\n1\n\n$ expr \"hello\" : \"wo.*\"\n0\n<\/code><\/pre>\n<p>\u5728\u5b57\u7b26\u4e32\u6bd4\u8f83\u4e2d\uff0c\u7b49\u53f7\uff08=\uff09\u8868\u793a\u76f8\u7b49\uff0c\u611f\u53f9\u53f7\u52a0\u7b49\u53f7\uff08!=\uff09\u8868\u793a\u4e0d\u76f8\u7b49\u3002\u5192\u53f7\u52a0\u6b63\u5219\u8868\u8fbe\u5f0f\uff08:\uff09\u7528\u4e8e\u5339\u914d\u5b57\u7b26\u4e32\u3002\u4e0a\u8ff0\u793a\u4f8b\u4e2d\uff0c\u7b2c\u4e00\u4e2a\u8868\u8fbe\u5f0f\u8fd4\u56de1\uff0c\u8868\u793a\u5b57\u7b26\u4e32\u76f8\u7b49\uff1b\u7b2c\u4e8c\u4e2a\u8868\u8fbe\u5f0f\u8fd4\u56de1\uff0c\u8868\u793a\u5b57\u7b26\u4e32\u4e0d\u76f8\u7b49\uff1b\u7b2c\u4e09\u4e2a\u8868\u8fbe\u5f0f\u8fd4\u56de1\uff0c\u8868\u793a\u5b57\u7b26\u4e32\u5339\u914d\uff1b\u7b2c\u56db\u4e2a\u8868\u8fbe\u5f0f\u8fd4\u56de0\uff0c\u8868\u793a\u5b57\u7b26\u4e32\u4e0d\u5339\u914d\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e5%8f%98%e9%87%8f-iXEnEUkOmZ\">\u4f7f\u7528\u53d8\u91cf<\/h2>\n<p>expr\u547d\u4ee4\u8fd8\u53ef\u4ee5\u4f7f\u7528\u53d8\u91cf\u8fdb\u884c\u8ba1\u7b97\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n<pre><code>$ x=5\n$ y=3\n$ expr $x + $y\n8\n<\/code><\/pre>\n<p>\u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0c\u6211\u4eec\u5b9a\u4e49\u4e86\u4e24\u4e2a\u53d8\u91cfx\u548cy\uff0c\u5e76\u5c06\u5b83\u4eec\u7684\u503c\u5206\u522b\u8bbe\u7f6e\u4e3a5\u548c3\u3002\u7136\u540e\uff0c\u6211\u4eec\u4f7f\u7528expr\u547d\u4ee4\u8ba1\u7b97\u4e86x\u548cy\u7684\u548c\uff0c\u7ed3\u679c\u4e3a8\u3002<\/p>\n<h2 id=\"%e6%80%bb%e7%bb%93-iXEnEUkOmZ\">\u603b\u7ed3<\/h2>\n<p>expr\u547d\u4ee4\u662f\u4e00\u4e2a\u975e\u5e38\u6709\u7528\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u5728Linux\u7cfb\u7edf\u4e2d\u8fdb\u884c\u8868\u8fbe\u5f0f\u8ba1\u7b97\u3002\u5b83\u652f\u6301\u6570\u5b66\u8fd0\u7b97\u3001\u5b57\u7b26\u4e32\u6bd4\u8f83\u548c\u5339\u914d\uff0c\u5e76\u4e14\u53ef\u4ee5\u4f7f\u7528\u53d8\u91cf\u8fdb\u884c\u8ba1\u7b97\u3002\u65e0\u8bba\u662f\u5728shell\u811a\u672c\u4e2d\u8fd8\u662f\u5728\u547d\u4ee4\u884c\u64cd\u4f5c\u4e2d\uff0cexpr\u547d\u4ee4\u90fd\u80fd\u591f\u63d0\u4f9b\u7075\u6d3b\u7684\u8ba1\u7b97\u529f\u80fd\u3002<\/p>\n<p>\u9999\u6e2f\u670d\u52a1\u5668\u9996\u9009\u540e\u6d6a\u4e91\uff0c\u63d0\u4f9b\u53ef\u9760\u7684\u4e91\u8ba1\u7b97\u670d\u52a1\u3002\u60a8\u53ef\u4ee5\u8bbf\u95ee<a href=\"https:\/\/idc.net\">https:\/\/idc.net<\/a>\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u9999\u6e2f\u670d\u52a1\u5668\u3001\u7f8e\u56fd\u670d\u52a1\u5668\u548c\u4e91\u670d\u52a1\u5668\u7684\u4fe1\u606f\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Linux \u547d\u4ee4\uff1aexpr - \u8ba1\u7b97\u8868\u8fbe\u5f0f Linux \u547d\u4ee4\uff1aexpr - \u8ba1\u7b97\u8868\u8fbe\u5f0f \u5728Linux\u7cfb\u7edf\u4e2d\uff0ce [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[27],"tags":[],"class_list":["post-210638","post","type-post","status-publish","format-standard","hentry","category-centos"],"_links":{"self":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts\/210638","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/comments?post=210638"}],"version-history":[{"count":0,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts\/210638\/revisions"}],"wp:attachment":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/media?parent=210638"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/categories?post=210638"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/tags?post=210638"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}