2 files changed, 29 insertions(+), 16 deletions(-)

M README.md
M mnc.go

@@ 14,15 14,28 @@ go build mnc.go
 
 ## Usage
 
+
+Returns the number of seconds until the next cronjob is due, use with ``crontab -l``:
+
+```sh
+crontab -l | mnc
+```
+
+Mnc reads from stdin and supports only crontab-style input
+
+## Use case
+
+A construction like this is used in Sxmo to wakeup the system when the next cronjob is due:
+
 ```sh
-sxmoscreenlock.sh rtc "$(mnc)"
+sxmoscreenlock.sh rtc "$(crontab -l | mnc)"
 ```
 
-Make sure you run this command via st on the phone rather than over ssh.
+In this use case, make sure you run this command via st on the phone rather than over ssh.
 
 ## Support and patches
 
-Send support questions and patches to the mailing list: 
+Send support questions and patches to the mailing list:
 [public inbox](https://lists.sr.ht/~anjan/public-inbox).
 
 Please use [git send-email](https://git-send-email.io/) and send a patch to my

@@ 6,7 6,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
-	"os/exec"
+	"os"
 	"strings"
 	"time"
 


@@ 25,25 25,28 @@ func init() {
 }
 
 func main() {
-	// parser is too clever and can try to parse the command as timespec fields six/seven
-	c := exec.Command("sh", "-c", "crontab -l | awk '{print $1\" \"$2\" \"$3\" \"$4\" \"$5}'")
-	r, _ := c.StdoutPipe()
-
 	// seed with a large number that rtcwake can still handle
 	m := 268435455
 	d := make(chan struct{})
-	s := bufio.NewScanner(r)
+	s := bufio.NewScanner(os.Stdin)
 
 	go func() {
 		n := time.Now()
 		for s.Scan() {
-			l := strings.TrimSpace(s.Text())
+			//we need to only get the first 5 fields otherwise
+			//the cron library will try to parse the rest too
+			fields := strings.Split(strings.TrimSpace(s.Text()), " ")
+			l := strings.Join(fields[:5], " ")
 			p, e := cron.ParseUTC(l)
 			if e == nil {
 				t, e := p.Next(n)
-				if e != nil { log.Fatal(e) }
+				if e != nil {
+					log.Fatal(e)
+				}
 				i := int(t.Sub(n).Seconds())
-				if i < m { m = i }
+				if i < m {
+					m = i
+				}
 				log.Print(i)
 			} else {
 				log.Print(e)


@@ 52,11 55,8 @@ func main() {
 		d <- struct{}{}
 	}()
 
-	e := c.Start()
-	if e != nil { log.Fatal(e) }
 	<-d
-	e = c.Wait()
-	if e != nil { log.Fatal(e) }
 
 	fmt.Println(m)
+
 }