mirror of
https://github.com/golang/go
synced 2024-11-22 00:14:42 -07:00
83f0b718ed
also add a section about compiling programs because some found it surprising not to have one R=rsc CC=go-dev http://go/go-review/1018011
47 lines
998 B
Go
47 lines
998 B
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"./file";
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"flag";
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"fmt";
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"os";
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)
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func cat(f *file.File) {
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const NBUF = 512;
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var buf [NBUF]byte;
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for {
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switch nr, er := f.Read(&buf); true {
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case nr < 0:
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fmt.Fprintf(os.Stderr, "cat: error reading from %s: %s\n", f.String(), er.String());
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os.Exit(1);
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case nr == 0: // EOF
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return;
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case nr > 0:
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if nw, ew := file.Stdout.Write(buf[0:nr]); nw != nr {
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fmt.Fprintf(os.Stderr, "cat: error writing from %s: %s\n", f.String(), ew.String());
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}
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}
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}
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}
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func main() {
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flag.Parse(); // Scans the arg list and sets up flags
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if flag.NArg() == 0 {
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cat(file.Stdin);
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}
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for i := 0; i < flag.NArg(); i++ {
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f, err := file.Open(flag.Arg(i), 0, 0);
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if f == nil {
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fmt.Fprintf(os.Stderr, "cat: can't open %s: error %s\n", flag.Arg(i), err);
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os.Exit(1);
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}
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cat(f);
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f.Close();
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}
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}
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