9ee2ce65b4
cat: usage function changed. tac: Fixed incorrect "ftac" function realization; usage function changed.
59 lines
904 B
Go
59 lines
904 B
Go
package cat
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/* Concatenate files in "stdout". */
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import(
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"os"
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"io"
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"flag"
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"fmt"
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)
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func cat(p string) error {
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f, e := os.Open(p)
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if e != nil {
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return e
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}
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defer f.Close()
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fcat(f)
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return nil
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}
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func fcat(f *os.File) error {
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b := make([]byte, 512)
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for {
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n, e := f.Read(b)
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if n>0 {
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fmt.Print(string(b[:n]))
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}
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if e == io.EOF {
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break
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}else if e != nil {
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return e
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}
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}
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return nil
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}
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func Run(args []string) int {
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status := 0
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arg0 := args[0]
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args = args[1:]
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flagSet := flag.NewFlagSet(arg0, flag.ExitOnError)
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flagSet.Usage = func() {
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fmt.Fprintf(os.Stderr, "Usage of %s: %s [files]\n", arg0, arg0)
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flagSet.PrintDefaults()
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}
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flagSet.Parse(args)
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args = flagSet.Args()
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if len(args)>0 {
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for _, p := range args {
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e := cat(p)
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if e != nil {
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fmt.Fprintf(os.Stderr, "%s: %s.\n", arg0, e)
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status = 1
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}
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}
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} else {
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fcat(os.Stdin)
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}
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return status
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}
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