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43 lines
720 B
43 lines
720 B
package main |
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import ( |
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"bufio" |
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"fmt" |
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"io" |
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"os" |
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"github.com/alexflint/go-arg" |
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common "source.heropunch.io/tomo/go-coreutils" |
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) |
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func head(num uint, reader io.Reader) { |
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scanner := bufio.NewScanner(reader) |
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for scanner.Scan() && num > 0 { |
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fmt.Println(scanner.Text()) |
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num = num - 1 |
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} |
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common.ExitIfError(scanner.Err()) |
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} |
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func main() { |
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var args struct { |
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Lines uint `arg:"-n"` |
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Files []string `arg:"positional"` |
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} |
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args.Lines = 10 |
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arg.MustParse(&args) |
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if len(args.Files) == 0 { |
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head(args.Lines, os.Stdin) |
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os.Exit(0) |
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} |
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for _, filename := range args.Files { |
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file, err := os.Open(filename) |
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common.ExitIfError(err) |
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head(args.Lines, file) |
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err = file.Close() |
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common.ExitIfError(err) |
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} |
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}
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