47 lines
776 B
Go
47 lines
776 B
Go
package main
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import "bufio"
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import "io"
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import "log"
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import "os"
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import "strings"
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func transform(in io.Reader, out io.Writer) {
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bufw := bufio.NewWriter(out)
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s := bufio.NewScanner(in)
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for s.Scan() {
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line := s.Text()
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for i, c := range line {
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if i == 0 {
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bufw.WriteString(strings.ToLower(string(c)))
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} else {
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bufw.WriteString(string(c))
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}
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}
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bufw.WriteString("\n")
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}
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}
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func main() {
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if len(os.Args) < 2 {
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log.Fatalln("Usage upper-line <file>")
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}
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f, err := os.Open(os.Args[1])
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if err != nil {
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log.Fatalln("Error opening file", err)
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}
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defer f.Close()
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var w io.Writer
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if len(os.Args) >= 3 {
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w, err = os.Create(os.Args[2])
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if err != nil {
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log.Fatalln("Error creating file", err)
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}
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} else {
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w = os.Stdout
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}
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transform(f, w)
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}
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