That's a really nice trick. Thanks for sharing. On Sunday, February 11, 2018 at 3:48:09 AM UTC-5, Michael Houston wrote: > > If you're using Bash or some other unix-y shell which supports it, you can > produce the same effect with built-in syntax: > > https://unix.stackexchange.com/a/64011 > > In Bash, you can use the command1 <( command0 ) redirection syntax, which >> redirects command0's stdout and passes it to a command1 that takes a >> filename as a command-line argument. This is called *process >> substitution* <https://en.wikipedia.org/wiki/Process_substitution>. >> > > Mike. > > > On Saturday, February 10, 2018 at 12:57:52 PM UTC, Or Rikon wrote: >> >> I actually fixed this a couple of days ago (see here >> <http://github.com/rikonor/stdio-wrapper>) without realizing what the >> issue was, but now I understand! Thank you! >> >> On Fri, Feb 9, 2018 at 10:27 PM Matt Harden <matt....@gmail.com> wrote: >> >>> You need to close fIn after the copy is done. As it is now, fIn.Close() >>> happens after io.Copy(os.Stdout, buf), which completes after your cat >>> command finishes. But cat won't finish until its input pipe returns EOF, >>> which happens after fIn.Close(). >>> >>> On Wed, Feb 7, 2018 at 5:46 PM Or Rikon <rik...@gmail.com> wrote: >>> >>>> Hi! >>>> >>>> I asked this previously on Stack Overflow but so far have not received >>>> a response, so I figured I will try here as well. >>>> >>>> I'm trying to wrap an executable that takes an input and output file >>>> paths as arguments, such that it will be possible to provide the input and >>>> output as stdin and stdout. >>>> >>>> I've written a short script in Go that attempts to do this, but for >>>> some reason which eludes me, it hangs forever. >>>> >>>> >>>> Here is the script: >>>> >>>> >>>> package main >>>> import ( >>>> "bytes" >>>> "io" >>>> "log" >>>> "os" >>>> "strings" >>>> "syscall" >>>> >>>> "golang.org/x/sync/errgroup") >>>> /* >>>> Expected behavior: >>>> >>>> # Terminal 1 >>>> $ go run main.go >>>> >>>> # Terminal 2 >>>> $ cat inPipe > outPipe >>>> >>>> The go program is writing to inPipe and reading from outPipe >>>> >>>> Actual behavior: The program stalls >>>> */ >>>> >>>> func main() { >>>> eg := &errgroup.Group{} >>>> >>>> inPipe := "inPipe" >>>> outPipe := "outPipe" >>>> >>>> if err := syscall.Mkfifo(inPipe, 0644); err != nil { >>>> log.Fatal(err) >>>> } >>>> defer os.Remove(inPipe) >>>> >>>> if err := syscall.Mkfifo(outPipe, 0644); err != nil { >>>> log.Fatal(err) >>>> } >>>> defer os.Remove(outPipe) >>>> >>>> fIn, err := os.OpenFile(inPipe, os.O_WRONLY, os.ModeNamedPipe) >>>> if err != nil { >>>> log.Fatal(err) >>>> } >>>> defer fIn.Close() >>>> >>>> eg.Go(func() error { >>>> _, err := io.Copy(fIn, strings.NewReader("123")) >>>> return err >>>> }) >>>> >>>> fOut, err := os.OpenFile(outPipe, os.O_RDONLY, os.ModeNamedPipe) >>>> if err != nil { >>>> log.Fatal(err) >>>> } >>>> defer fOut.Close() >>>> >>>> buf := &bytes.Buffer{} >>>> >>>> eg.Go(func() error { >>>> _, err := io.Copy(buf, fOut) >>>> return err >>>> }) >>>> >>>> if err := eg.Wait(); err != nil { >>>> log.Fatal(err) >>>> } >>>> >>>> if _, err := io.Copy(os.Stdout, buf); err != nil { >>>> log.Fatal(err) >>>> }} >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "golang-nuts" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to golang-nuts...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>>
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