{"id":21571,"date":"2022-11-14T07:25:13","date_gmt":"2022-11-14T01:55:13","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-how-do-i-replace-a-line-in-a-file-using-perl\/"},"modified":"2022-11-14T07:25:13","modified_gmt":"2022-11-14T01:55:13","slug":"solved-how-do-i-replace-a-line-in-a-file-using-perl","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-how-do-i-replace-a-line-in-a-file-using-perl\/","title":{"rendered":"[Solved] How do I replace a line in a file using Perl?"},"content":{"rendered":"<p> [ad_1]<br \/>\n<\/p>\n<div id=\"answer-9232312\" class=\"answer js-answer accepted-answer js-accepted-answer\" data-answerid=\"9232312\" data-parentid=\"9230171\" data-score=\"2\" data-position-on-page=\"1\" data-highest-scored=\"1\" data-question-has-accepted-highest-score=\"1\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\">\n<div class=\"post-layout\">\n<div class=\"votecell post-layout--left\"><\/div>\n<div class=\"answercell post-layout--right\">\n<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>The only actual problem with your code was that you were printing the line to the new file in the wrong place in the loop. You need to print every line from the old file into the new file.<\/p>\n<p>Having tidied your file a little and updated some of the idioms, I end up with this:<\/p>\n<pre><code>#!\/usr\/bin\/perl\n\nuse strict;\nuse warnings;\nuse 5.010;\n\nmy $old_file=\"in.txt\";\nmy $new_file=\"out.txt\";\n\nmy $CD_VER = 'CD29';\n\nopen my $rf, '&lt;', $old_file or die \"Cannot open $old_file for reading.\";\nopen my $wf, '&gt;'. $new_file or die \"Cannot open $new_file for writing.\";\n\nwhile ( &lt;$rf&gt; ) {\n    if (\/CODEDROP\/ and \/regular\/) {\n        s\/regular\/$CD_VER\/ ;\n    }\n    print $wf $_;\n}\n\nclose $rf;\nclose $wf;\n<\/code><\/pre>\n<\/p><\/div>\n<div class=\"mt24\"><\/div>\n<\/div>\n<p>            <span class=\"d-none\" itemprop=\"commentCount\">2<\/span> <\/p><\/div>\n<\/div>\n<p>[ad_2]<\/p>\n<p>solved How do I replace a line in a file using Perl? <\/p>\n","protected":false},"excerpt":{"rendered":"<p>[ad_1] The only actual problem with your code was that you were printing the line to the new file in the wrong place in the loop. You need to print every line from the old file into the new file. Having tidied your file a little and updated some of the idioms, I end up &#8230; <a title=\"[Solved] How do I replace a line in a file using Perl?\" class=\"read-more\" href=\"https:\/\/jassweb.com\/solved\/solved-how-do-i-replace-a-line-in-a-file-using-perl\/\" aria-label=\"More on [Solved] How do I replace a line in a file using Perl?\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[320],"tags":[442],"class_list":["post-21571","post","type-post","status-publish","format-standard","hentry","category-solved","tag-perl"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>[Solved] How do I replace a line in a file using Perl? - JassWeb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/jassweb.com\/solved\/solved-how-do-i-replace-a-line-in-a-file-using-perl\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"[Solved] How do I replace a line in a file using Perl? - JassWeb\" \/>\n<meta property=\"og:description\" content=\"[ad_1] The only actual problem with your code was that you were printing the line to the new file in the wrong place in the loop. 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