diff options
Diffstat (limited to 'weed/util/fla9/fla9.go')
| -rw-r--r-- | weed/util/fla9/fla9.go | 128 |
1 files changed, 74 insertions, 54 deletions
diff --git a/weed/util/fla9/fla9.go b/weed/util/fla9/fla9.go index 8fad9144b..8cea07311 100644 --- a/weed/util/fla9/fla9.go +++ b/weed/util/fla9/fla9.go @@ -3,63 +3,78 @@ // license that can be found in the LICENSE file. /* - Package flag implements command-line flag parsing. +Package flag implements command-line flag parsing. - Usage: +Usage: - Define flags using flag.String(), Bool(), Int(), etc. +Define flags using flag.String(), Bool(), Int(), etc. - This declares an integer flag, -flagname, stored in the pointer ip, with type *int. - import "flag" - var ip = flag.Int("flagname", 1234, "help message for flagname") - If you like, you can bind the flag to a variable using the Var() functions. - var flagvar int - func init() { - flag.IntVar(&flagvar, "flagname", 1234, "help message for flagname") - } - Or you can create custom flags that satisfy the Value interface (with - pointer receivers) and couple them to flag parsing by - flag.Var(&flagVal, "name", "help message for flagname") - For such flags, the default value is just the initial value of the variable. - - After all flags are defined, call - flag.Parse() - to parse the command line into the defined flags. - - Flags may then be used directly. If you're using the flags themselves, - they are all pointers; if you bind to variables, they're values. - fmt.Println("ip has value ", *ip) - fmt.Println("flagvar has value ", flagvar) - - After parsing, the arguments following the flags are available as the - slice flag.Args() or individually as flag.Arg(i). - The arguments are indexed from 0 through flag.NArg()-1. - - Command line flag syntax: - -flag - -flag=x - -flag x // non-boolean flags only - One or two minus signs may be used; they are equivalent. - The last form is not permitted for boolean flags because the - meaning of the command - cmd -x * - will change if there is a file called 0, false, etc. You must - use the -flag=false form to turn off a boolean flag. - - Flag parsing stops just before the first non-flag argument - ("-" is a non-flag argument) or after the terminator "--". - - Integer flags accept 1234, 0664, 0x1234 and may be negative. - Boolean flags may be: - 1, 0, t, f, T, F, true, false, TRUE, FALSE, True, False - Duration flags accept any input valid for time.ParseDuration. - - The default set of command-line flags is controlled by - top-level functions. The FlagSet type allows one to define - independent sets of flags, such as to implement subcommands - in a command-line interface. The methods of FlagSet are - analogous to the top-level functions for the command-line - flag set. +This declares an integer flag, -flagname, stored in the pointer ip, with type *int. + + import "flag" + var ip = flag.Int("flagname", 1234, "help message for flagname") + +If you like, you can bind the flag to a variable using the Var() functions. + + var flagvar int + func init() { + flag.IntVar(&flagvar, "flagname", 1234, "help message for flagname") + } + +Or you can create custom flags that satisfy the Value interface (with +pointer receivers) and couple them to flag parsing by + + flag.Var(&flagVal, "name", "help message for flagname") + +For such flags, the default value is just the initial value of the variable. + +After all flags are defined, call + + flag.Parse() + +to parse the command line into the defined flags. + +Flags may then be used directly. If you're using the flags themselves, +they are all pointers; if you bind to variables, they're values. + + fmt.Println("ip has value ", *ip) + fmt.Println("flagvar has value ", flagvar) + +After parsing, the arguments following the flags are available as the +slice flag.Args() or individually as flag.Arg(i). +The arguments are indexed from 0 through flag.NArg()-1. + +Command line flag syntax: + + -flag + -flag=x + -flag x // non-boolean flags only + +One or two minus signs may be used; they are equivalent. +The last form is not permitted for boolean flags because the +meaning of the command + + cmd -x * + +will change if there is a file called 0, false, etc. You must +use the -flag=false form to turn off a boolean flag. + +Flag parsing stops just before the first non-flag argument +("-" is a non-flag argument) or after the terminator "--". + +Integer flags accept 1234, 0664, 0x1234 and may be negative. +Boolean flags may be: + + 1, 0, t, f, T, F, true, false, TRUE, FALSE, True, False + +Duration flags accept any input valid for time.ParseDuration. + +The default set of command-line flags is controlled by +top-level functions. The FlagSet type allows one to define +independent sets of flags, such as to implement subcommands +in a command-line interface. The methods of FlagSet are +analogous to the top-level functions for the command-line +flag set. */ package fla9 @@ -458,8 +473,10 @@ func (f *FlagSet) PrintDefaults() { // a usage message showing the default settings of all defined // command-line flags. // For an integer valued flag x, the default output has the form +// // -x int // usage-message-for-x (default 7) +// // The usage message will appear on a separate line for anything but // a bool flag with a one-byte name. For bool flags, the type is // omitted and if the flag name is one byte the usage message appears @@ -469,8 +486,11 @@ func (f *FlagSet) PrintDefaults() { // string; the first such item in the message is taken to be a parameter // name to show in the message and the back quotes are stripped from // the message when displayed. For instance, given +// // flag.String("I", "", "search `directory` for include files") +// // the output will be +// // -I directory // search directory for include files. func PrintDefaults() { CommandLine.PrintDefaults() } |