This question already has an answer here:
I wrote some code in Go to call vmstat to pull some statistics data. There are several variations to the cmdArgs and I annotated which are working and which are not:
1 package main
2
3 import (
4 "bufio"
5 "fmt"
6 "os"
7 "os/exec"
8 )
9
10 func main() {
11 // cmdName := "sar"
12 // cmdArgs := []string{"-n DEV 1 1"}
13 cmdName := "vmstat"
14
15 // cmdArgs := []string{"-tSm 1 1"} //<--- This works but does
16 // not produce desired output
17
18 cmdArgs := []string{"-t -Sm 1 1"} //<--- This works but does
19 // not produce desired output
20
21 // cmdArgs := []string{"-Sm 1 1", "-t"} //<--- This does NOT work
22 // cmdArgs := []string{"-t","-Sm 1 1"} //<--- This does NOT work
23
24 cmd := exec.Command(cmdName, cmdArgs...)
25 cmdReader, err := cmd.StdoutPipe()
26 if err != nil {
27 fmt.Fprintln(os.Stderr, "Error creating StdoutPipe for Cmd", err)
28 os.Exit(1)
29 }
30
31 scanner := bufio.NewScanner(cmdReader)
32 go func() {
33 for scanner.Scan() {
34 fmt.Printf("%s
", scanner.Text())
35 }
36 }()
37
38 err = cmd.Start()
39 if err != nil {
40 fmt.Fprintln(os.Stderr, "Error starting Cmd", err)
41 os.Exit(1)
42 }
43
44 err = cmd.Wait()
45 if err != nil {
46 fmt.Fprintln(os.Stderr, "Error waiting for Cmd", err)
47 os.Exit(1)
48 }
49 }
Bottom line is I want to get the data in Megabytes and if I run the following on my shell, it works:
# vmstat -t -Sm 1 1
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ ---timestamp---
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 1 201 4544 190 7970 0 0 85 32 1 1 1 0 97 2 0 2018-06-21 16:52:13 EDT
# vmstat -Sm -t 1 1
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ ---timestamp---
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 1 201 4496 191 8012 0 0 85 32 1 1 1 0 97 2 0 2018-06-21 16:52:33 EDT
My question is - what is the acceptable way to arrange the arguments and still get the desired output? Also, I have a similar issue with sar(I am trying to pull network interface stats), but I cannot get it to accept any variation of the arguments:
1 package main
2
3 import (
4 "bufio"
5 "fmt"
6 "os"
7 "os/exec"
8 )
9
10 func main() {
11 cmdName := "sar"
12 cmdArgs := []string{"-n DEV 1 1"} //<--- This does NOT work
13
14 // cmdArgs := []string{"-n DEV","1 1"} //<--- This does NOT work
15
16 cmd := exec.Command(cmdName, cmdArgs...)
17 cmdReader, err := cmd.StdoutPipe()
18 if err != nil {
19 fmt.Fprintln(os.Stderr, "Error creating StdoutPipe for Cmd", err)
20 os.Exit(1)
21 }
22
23 scanner := bufio.NewScanner(cmdReader)
24 go func() {
25 for scanner.Scan() {
26 fmt.Printf("%s
", scanner.Text())
27 }
28 }()
29
30 err = cmd.Start()
31 if err != nil {
32 fmt.Fprintln(os.Stderr, "Error starting Cmd", err)
33 os.Exit(1)
34 }
35
36 err = cmd.Wait()
37 if err != nil {
38 fmt.Fprintln(os.Stderr, "Error waiting for Cmd", err)
39 os.Exit(1)
40 }
41 }
Here is how I call sar from the shell:
$ sar -n DEV 1 1
Linux 2.6.32-696.18.7.el6.x86_64 (invenioq.gmu.edu) 06/21/2018 _x86_64_ (2 CPU)
05:08:56 PM IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s txcmp/s rxmcst/s
05:08:57 PM lo 0.00 0.00 0.00 0.00 0.00 0.00 0.00
05:08:57 PM eth0 3.96 0.00 0.24 0.00 0.00 0.00 0.00
05:08:57 PM eth1 2.97 0.00 0.17 0.00 0.00 0.00 0.00
Average: IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s txcmp/s rxmcst/s
Average: lo 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Average: eth0 3.96 0.00 0.24 0.00 0.00 0.00 0.00
Average: eth1 2.97 0.00 0.17 0.00 0.00 0.00 0.00
I appreciate any feedback/help. Thank you
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