2009年11月13日 · go run main.go Try out the run program by first giving it without flags. Note that if you omit flags they automatically take their default values. go run command-line-flags.go --env production --port 2000 If you provide a flag with specified value then default will overwrite by …

2021年6月9日 · $ go run main.go foo -required hello -required is required for all commands flag provided but not defined: -required Usage of foo: exit status 2 It looks like flag.Parse() is not capturing -required from the CLI, and then the fooCmd is complaining that I've given it a flag it doesn't recognize.

2014年8月9日 · Beware though, all flags after the first positional flags are treated as positional. So go run main arg1 --flag1=1 --flag2=2 will actually show as flag.NArg() == 3, and dashed flags won't be parsed but will show up as positional.

package main // Go provides a `flag` package supporting basic // command-line flag parsing. We'll use this package to // implement our example command-line program. import "flag" import "fmt" func main() { // Basic flag declarations are available for string, // integer, and boolean options.

+1. The flag.Value() method can also be used if you want to specify all list elements in one comma separated string which Value() can split into a slice of strings. flag.Value and flag.Var() is much more general than just using flag.String() and strings.Split(). Errors reported by Value() are also handled automatically by package flag. –

2013年11月4日 · The global flag.Parse() function doesn't accept an argument to parse. This code example can than be run in the tour of go code pad where you can't provide command lines arguments. This code example can than be run in the tour of go code pad where you can't provide command lines arguments.

2022年1月25日 · go; go-flag; Share. Improve this question. Follow asked Jan 25, 2022 at 20:44. Oscar P Oscar P. 417 1 1 ...

2015年8月3日 · Here's a full working example. Work around the Usage and DefValue attributes, and wrap your flags into a struct. ...

2013年7月2日 · EDIT: In answer to how to run unit tests against flags, the most canonical example is flag_test.go in the flag package source. The section related to testing custom flag variables starts at Line 181 .

2021年6月19日 · go run main.go -t abc abc if -t flag not used or not value parse for it, No other function calls. It will print nothin in my example. go run main.go You can use this for every flagged variable. And run your output() function call when you want to call it anywhere because you have set default value for -o flag.