{"id":7757,"date":"2026-07-08T11:00:47","date_gmt":"2026-07-08T03:00:47","guid":{"rendered":"https:\/\/www.5x44.cn\/?p=7757"},"modified":"2026-07-08T11:32:02","modified_gmt":"2026-07-08T03:32:02","slug":"bash-%e5%8f%82%e6%95%b0%e5%90%8d%e5%b1%95%e5%bc%80","status":"publish","type":"post","link":"https:\/\/www.5x44.cn\/?p=7757","title":{"rendered":"BASH \u53c2\u6570\u540d\u5c55\u5f00${}"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">${}\u7684\u5168\u540d\u662f\uff1a\u53c2\u6570\u5c55\u5f00(Parameter Expansion)\uff0c\u5bf9\u53c2\u6570\u505a\u64cd\u4f5c\u7684\u8bed\u6cd5\u3002\u5bf9\u67d0\u4e2a\u201c\u53c2\u6570\u201d\u8fdb\u884c\u52a0\u5de5\u540e\u518d\u53d6\u503c\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">\u8fd9\u91cc\u7684\u53c2\u6570\u5305\u62ec\uff1a\u666e\u901a\u53d8\u91cf\u3001\u4f4d\u7f6e\u53c2\u6570\u3001\u6570\u7ec4\u3001\u7279\u6b8a\u53d8\u91cf\uff08#\uff0c *\uff0c @ \uff09<\/p>\n<\/blockquote>\n\n\n\n<p class=\"has-vivid-cyan-blue-background-color has-background has-medium-font-size wp-block-paragraph\">\u7b2c\u4e00\u7c7b\uff1a\u660e\u786e\u8fb9\u754c\uff0c\u544a\u8bc9bash\u53d8\u91cf\u540d\u5230\u54ea\u91cc\u7ed3\u675f<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>${var}<\/li>\n\n\n\n<li>${var[0]}<\/li>\n\n\n\n<li>${10}\uff08\u4f4d\u7f6e\u53c2\u6570\uff0c$0\u547d\u4ee4\u540d\uff0c$1\u7b2c\u4e00\u4e2a\u4f4d\u7f6e\u53c2\u6570\uff0c\u5f53\u8d85\u8fc79\u65f6\u5c31\u5fc5\u987b\u4f7f\u7528\u82b1\u62ec\u53f7\uff0c\u4e0d\u7136\u4f1a\u88ab\u89e3\u6790\u6210$1\u548c0\uff09<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u7528\u4e8e\u533a\u5206\u5b57\u7b26\u4e32\u4e2d\u54ea\u4e9b\u5b57\u7b26\u662f\u53d8\u91cf\u3002<\/p>\n\n\n\n<p class=\"has-vivid-cyan-blue-background-color has-background has-medium-font-size wp-block-paragraph\">\u7b2c\u4e8c\u7c7b\uff1a\u5b57\u7b26\u4e32\u5904\u7406<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\"><strong>\u529f\u80fd<\/strong><\/th><th class=\"has-text-align-left\" data-align=\"left\"><strong>\u5199\u6cd5<\/strong><\/th><th class=\"has-text-align-left\" data-align=\"left\"><strong>\u8bb0\u5fc6<\/strong><\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">\u5207\u7247<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>${var:\u8d77\u70b9:\u957f\u5ea6}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u50cf Python<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u957f\u5ea6<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>${#var}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>#<\/code>= count\uff0c\u6ce8\u610f\u533a\u5206\u524d\u7f00\u5220\u9664<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u66ff\u6362<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>${var\/old\/new}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>\/<\/code>= replace<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u8d2a\u5a6a\u66ff\u6362<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>${var\/\/old\/new}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>\/\/<\/code>= \u5168\u90e8<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u524d\u7f00\u5220\u9664<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>${var#pattern}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>#<\/code>= \u5220\u9664\u5305\u542bpattern\u5728\u5185\u5de6\u8fb9\u5185\u5bb9<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u540e\u7f00\u5220\u9664<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>${var%pattern}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>%<\/code>= \u5220\u9664\u5305\u542bpattern\u5728\u5185\u53f3\u8fb9\u5185\u5bb9<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">\u8868\u683c\u4e2d\u8d2a\u5a6a\u66ff\u6362\u4f7f\u7528\u4e86\u53cc\u659c\u7ebf\u201c\/\/\u201d\uff0c\u8868\u793a\u66ff\u6362\u6240\u6709\u3002\u4e0b\u9762\u7684\u524d\u3001\u540e\u7f00\u5220\u9664\u4e5f\u540c\u6837\u9002\u7528\u201c\u8d2a\u5a6a\u201d\u5220\u9664\u201c##\u201d\u201c%%\u201d\uff0c\u5176\u4e2d\u7684pattern\u662f\u201cFilename Expansion Pattern\uff08\u6587\u4ef6\u540d\u901a\u914d\u7b26\uff09\u201d<\/p>\n\n\n\n<p class=\"has-light-green-cyan-background-color has-background wp-block-paragraph\">\u6587\u4ef6\u540d\u901a\u914d\u7b26<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\"><strong>\u7b26\u53f7<\/strong><\/th><th class=\"has-text-align-left\" data-align=\"left\"><strong>\u542b\u4e49<\/strong><\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>*<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u4efb\u610f\u957f\u5ea6\u4efb\u610f\u5b57\u7b26<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>?<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u4efb\u610f\u4e00\u4e2a\u5b57\u7b26<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>[abc]<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">a \/ b \/ c \u4e4b\u4e00<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>[a-z]<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u4e00\u4e2a\u8303\u56f4<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>[^a-z]<\/code>\/ <code>[!a-z]<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u4e0d\u5728\u8303\u56f4\u5185<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"has-vivid-cyan-blue-background-color has-background has-medium-font-size wp-block-paragraph\">\u7b2c\u4e09\u7c7b\uff1a\u8d4b\u503c\/\u5bb9\u9519<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\"><strong>\u5199\u6cd5<\/strong><\/th><th class=\"has-text-align-left\" data-align=\"left\"><strong>\u542b\u4e49<\/strong><\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>${var:-default}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u672a\u5b9a\u4e49\u6216\u4e3a\u7a7a \u2192 default<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>${var:=default}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u672a\u5b9a\u4e49\u6216\u4e3a\u7a7a \u2192 \u8d4b\u503c<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>${var:?error_message}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u672a\u5b9a\u4e49 \u2192 \u62a5\u9519\u9000\u51fa<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\"><code>${var:+value}<\/code><\/td><td class=\"has-text-align-left\" data-align=\"left\">\u5df2\u5b9a\u4e49 \u2192 value<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>${}\u7684\u5168\u540d\u662f\uff1a\u53c2\u6570\u5c55\u5f00(Parameter Expansion)\uff0c\u5bf9\u53c2\u6570\u505a\u64cd\u4f5c\u7684\u8bed\u6cd5\u3002\u5bf9\u67d0\u4e2a\u201c\u53c2\u6570\u201d\u8fdb\u884c\u52a0\u5de5\u540e\u518d\u53d6\u503c\u3002 \u8fd9\u91cc\u7684\u53c2\u6570\u5305\u62ec\uff1a\u666e\u901a\u53d8\u91cf\u3001\u4f4d\u7f6e\u53c2\u6570\u3001\u6570&#8230;<\/p>\n<p class=\"read-more\"><a class=\"btn btn-default\" href=\"https:\/\/www.5x44.cn\/?p=7757\"> Read More<span class=\"screen-reader-text\">  Read More<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-7757","post","type-post","status-publish","format-standard","hentry","category-it"],"_links":{"self":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/7757","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7757"}],"version-history":[{"count":10,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/7757\/revisions"}],"predecessor-version":[{"id":7767,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/7757\/revisions\/7767"}],"wp:attachment":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7757"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7757"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7757"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}