tmp

Create a temporary file and write to it

Description

tmp creates a temporary file, writes the contents of STDIN to it then returns its filename to STDOUT.

You can optionally specify a file extension, for example if the temporary file needs to be read by open or an editor which uses extensions to define syntax highlighting.

Usage

`<stdin>` -> tmp [ file-extension ] -> `<stdout>`

Examples

» out: "Hello, world!" -> set: tmp

» out: $tmp
/var/folders/3t/267q_b0j27d29bnf6pf7m7vm0000gn/T/murex838290600/8ec6936c1ac1c347bf85675eab4a0877-13893

» open: $tmp
Hello, world!

Detail

The temporary file name is a base64 encoded md5 hash of the time plus Murex function ID with Murex process ID appended:

package io

import (
	"crypto/md5"
	"encoding/hex"
	"io"
	"os"
	"strconv"
	"time"

	"github.com/lmorg/murex/lang"
	"github.com/lmorg/murex/lang/types"
	"github.com/lmorg/murex/utils/consts"
)

func init() {
	lang.DefineMethod("tmp", cmdTempFile, types.Any, types.String)
}

func cmdTempFile(p *lang.Process) error {
	p.Stdout.SetDataType(types.String)

	ext, _ := p.Parameters.String(0)
	if ext != "" {
		ext = "." + ext
	}

	fileId := time.Now().String() + ":" + strconv.Itoa(int(p.Id))

	h := md5.New()
	_, err := h.Write([]byte(fileId))
	if err != nil {
		return err
	}

	name := consts.TempDir + hex.EncodeToString(h.Sum(nil)) + "-" + strconv.Itoa(os.Getpid()) + ext

	file, err := os.Create(name)
	if err != nil {
		return err
	}

	defer file.Close()

	_, err = io.Copy(file, p.Stdin)
	if err != nil {
		return err
	}

	_, err = p.Stdout.Write([]byte(name))
	return err
}

This should should provide enough distance to run tmp in parallel....should you ever want to.

tmp files are also located inside a unique per-process Murex temp directory which itself is located in the appropriate temp directory for the host OS (eg $TMPDIR on macOS).

See Also

• >> (append file): Writes STDIN to disk - appending contents if file already exists
• > (truncate file): Writes STDIN to disk - overwriting contents if file already exists
• open: Open a file with a preferred handler
• pipe: Manage Murex named pipes