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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 22 |
1 files changed, 21 insertions, 1 deletions
@@ -120,6 +120,23 @@ $ WORKERS='1,99' ./example Workers: [1 99] ``` +You can also have an environment variable that doesn't match the arg name: + +```go +var args struct { + Workers int `arg:"--count,env:NUM_WORKERS"` +} +arg.MustParse(&args) +fmt.Println("Workers:", args.Workers) +``` + +``` +$ NUM_WORKERS=6 ./example +Workers: 6 +$ NUM_WORKERS=6 ./example --count 4 +Workers: 4 +``` + ### Usage strings ```go var args struct { @@ -284,6 +301,9 @@ $ ./example --version someprogram 4.3.0 ``` +> **Note** +> If a `--version` flag is defined in `args` or any subcommand, it overrides the built-in versioning. + ### Overriding option names ```go @@ -591,7 +611,7 @@ https://godoc.org/github.com/alexflint/go-arg There are many command line argument parsing libraries for Go, including one in the standard library, so why build another? -The `flag` library that ships in the standard library seems awkward to me. Positional arguments must preceed options, so `./prog x --foo=1` does what you expect but `./prog --foo=1 x` does not. It also does not allow arguments to have both long (`--foo`) and short (`-f`) forms. +The `flag` library that ships in the standard library seems awkward to me. Positional arguments must precede options, so `./prog x --foo=1` does what you expect but `./prog --foo=1 x` does not. It also does not allow arguments to have both long (`--foo`) and short (`-f`) forms. Many third-party argument parsing libraries are great for writing sophisticated command line interfaces, but feel to me like overkill for a simple script with a few flags. |