\nThe \nThe <\/CODE>\/F<\/CODE> switch in conjunction with the single quotation\nmarks indicates that the quoted string is a command to run, whose output\nis then to be parsed and returned in the specified variable (or variables).\nThe option \nThe kludgy batch language gets even kludgier.\nWhy is the batch language such a grammatical mess?\nBackwards compatibility.\n<\/P>\n \nAny change to the batch language cannot break compatibility with the\nmillions of batch programs already in existence.\nSuch batch files are burned onto millions of CDs\n(you’d be surprised how many commercial programs use batch files,\nparticularly as part of their installation process).\nThey’re also run by corporations around the world\nto get their day-to-day work done.\nPlus of course the batch files written by people like you and me\nto do a wide variety of things.\nAny change to the batch language must keep these batch files running.\n<\/P>\n \nOf course, one could invent a brand new batch language,\nlet’s call it Batch² for the sake of discussion, and thereby\nbe rid of the backwards compatibility constraints.\nBut with that decision come different obstacles.\n<\/P>\n \nSuppose you have a 500-line batch file and you want to add one little\nfeature to it, but that new feature is available only in Batch².\nDoes this mean that you have to do a complete rewrite of your batch\nprogram into Batch²?\nYour company spent years tweaking this batch file over the years.\n(And by “tweaking” I might mean “turning into a plate of spaghetti”.)\nDo you want to take the risk of introducing who-knows-how-many bugs\nand breaking various obscure features as part of the rewrite into\nBatch²?\n<\/P>\n \nSuppose you decide to bite the bullet and rewrite.\nOh, but Batch² is available only in more recent\nversions of Windows.\nDo you tell your customers, “We don’t support the older versions of\nWindows any more”?\nOr do you bite another bullet and say, “We support only versions of\nWindows that have Batch²”?\n<\/P>\n \nI’m not saying that it won’t happen.\n(In fact, I’m under the impression that there are already efforts to\ndesign\n\na new command console language with an entirely new grammar<\/A>.\nSaid effort\n\nmight even be presenting at the PDC in a few days<\/A>.)\nI’m just explaining why the classic batch language is such a mess.\nWelcome to evolution.\n<\/P>\n \n[Raymond is currently away; this message was pre-recorded.]\n<\/P><\/p>\n","protected":false},"excerpt":{"rendered":" The FOR command has become the batch language’s looping construct. If you ask for help via FOR \/? you can see all the ways it has become overloaded. For example, you can read the output of a command by using the for command. FOR \/F “tokens=*” %i IN (‘ver’) DO echo %i The \/F switch […]<\/p>\n","protected":false},"author":1069,"featured_media":111744,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[25],"class_list":["post-34263","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":" The FOR command has become the batch language’s looping construct. If you ask for help via FOR \/? you can see all the ways it has become overloaded. For example, you can read the output of a command by using the for command. FOR \/F “tokens=*” %i IN (‘ver’) DO echo %i The \/F switch […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/34263","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/users\/1069"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/comments?post=34263"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/34263\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media\/111744"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media?parent=34263"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=34263"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=34263"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}FOR<\/CODE> command has become the batch language’s\nlooping construct.\nIf you ask for help via FOR \/?<\/CODE> you can see all the\nways it has become overloaded.\nFor example,\nyou can read the output of a command\nby using the for<\/CODE> command.\n<\/P>\n\nFOR \/F “tokens=*” %i IN (‘ver’) DO echo %i\n<\/PRE>\n
“tokens=*”<\/CODE> says that the entire line should be\ncollected. There are several other options that control the parsing,\nwhich I leave you to read on your own.\n<\/P>\n