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34 lines
950 B
Go
34 lines
950 B
Go
// [Environment variables](http://en.wikipedia.org/wiki/Environment_variable)
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// are a universal mechanism for [conveying configuration
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// information to Unix programs](http://www.12factor.net/config).
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// Let's look at how to set, get, and list environment variables.
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package main
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import (
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"fmt"
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"os"
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"strings"
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)
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func main() {
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// To set a key/value pair, use `os.Setenv`. To get a
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// value for a key, use `os.Getenv`. This will return
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// an empty string if the key isn't present in the
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// environment.
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os.Setenv("FOO", "1")
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fmt.Println("FOO:", os.Getenv("FOO"))
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fmt.Println("BAR:", os.Getenv("BAR"))
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// Use `os.Environ` to list all key/value pairs in the
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// environment. This returns a slice of strings in the
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// form `KEY=value`. You can `strings.SplitN` them to
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// get the key and value. Here we print all the keys.
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fmt.Println()
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for _, e := range os.Environ() {
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pair := strings.SplitN(e, "=", 2)
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fmt.Println(pair[0])
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}
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}
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