seasharp/go-coreutils
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dtluna 2019-03-26 15:52:29 +03:00
parent d094be6014
commit b8b468f0b8
5 changed files with 62 additions and 4 deletions
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2
README.md
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@ -36,7 +36,7 @@ Utilities:
* [ ] `fold`
* [ ] `getconf`
* [ ] `grep`
* [ ] `head`
* [x] `head`
* [ ] `hostname`
* [ ] `join`
* [ ] `kill`

13
error.go Normal file
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@ -0,0 +1,13 @@
package common
import (
"fmt"
"os"
)
func ExitIfError(err error) {
if err != nil {
fmt.Fprintf(os.Stderr, "%v: %v\n", os.Args[0], err)
os.Exit(1)
}
}

5
go.mod
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@ -1,3 +1,6 @@
module source.heropunch.io/tomo/go-coreutils
require github.com/stretchr/testify v1.3.0
require (
github.com/alexflint/go-arg v1.0.0
github.com/stretchr/testify v1.3.0
)

9
go.sum
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@ -1,7 +1,16 @@
github.com/alexflint/go-arg v1.0.0 h1:VWNnY3DyBHiq5lcwY2FlCE5t5qyHNV0o5i1bkCIHprU=
github.com/alexflint/go-arg v1.0.0/go.mod h1:Cto8k5VtkP4pp0EXiWD4ZJMFOOinZ38ggVcQ/6CGuRI=
github.com/alexflint/go-scalar v1.0.0 h1:NGupf1XV/Xb04wXskDFzS0KWOLH632W/EO4fAFi+A70=
github.com/alexflint/go-scalar v1.0.0/go.mod h1:GpHzbCOZXEKMEcygYQ5n/aa4Aq84zbxjy3MxYW0gjYw=
github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=

37
head/head.go
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@ -1,10 +1,43 @@
package main
import (
"bufio"
"fmt"
"io"
"os"
"github.com/alexflint/go-arg"
common "source.heropunch.io/tomo/go-coreutils"
)
func main() {
fmt.Println(os.Args)
func head(num uint, reader io.Reader) {
scanner := bufio.NewScanner(reader)
for scanner.Scan() && num > 0 {
fmt.Println(scanner.Text())
num = num - 1
}
common.ExitIfError(scanner.Err())
}
func main() {
var args struct {
Lines uint `arg:"-n"`
Files []string `arg:"positional"`
}
args.Lines = 10
arg.MustParse(&args)
if len(args.Files) == 0 {
head(args.Lines, os.Stdin)
os.Exit(0)
}
for _, filename := range args.Files {
file, err := os.Open(filename)
common.ExitIfError(err)
head(args.Lines, file)
err = file.Close()
common.ExitIfError(err)
}
}