I have a shell command
set -a source /etc/environment; set +a
I want to run this command to refresh my env file
the code I tried to do
cmd, err := exec.Command("bash", "set -a source /etc/environment; set +a").Output()
fmt.Println("cmd=================>", cmd)
if err != nil {
fmt.Println(err)
}
it gave me exit status 127
try this
cmd, err := exec.Command("bash","-c", "set -a source /etc/environment; set +a").Output()
fmt.Println("cmd=================>", cmd)
if err != nil {
fmt.Println(err)
}
Related
cmdstr := "ssh -i ....... blah blah blah" ssh to an ip and run rpm command to install rpm
cmd := exec.Command("/bin/bash", "-c", cmdstr)
var out bytes.Buffer
cmd.Stdout = &out
err := cmd.Run()
if err != nil {
fmt.Println(out.String())
}
out.String() does not print anything
if I have ping command without /bin/bash it prints the out. Anyone knows why ?
cmd.Stdout captures the output of a successful command execution
cmd.Stderr captures the command output if an error occurs during execution
You could try the cmd.Output() variant and capture execution errors from Stderr using
cmdstr := "ssh -i ....... blah blah blah" // ssh to an ip and run rpm command to install rpm
cmd := exec.Command("/bin/bash", "-c", cmdstr)
var errb bytes.Buffer
cmd.Stderr = &errb
output, err := cmd.Output()
if err != nil {
fmt.Printf("error: %s", errb.String()) // capture any error output
}
fmt.Println(string(output)) // when successful
I am attempting to run the following code in Go. I have tried both of the following ways:
out, err := exec.Command("sh", "-c", "tcpdump -i ens0 host 192.168.1.100 -F ./testfile").Output()
fmt.Println(string(out)) // Prints nothing
fmt.Println(err) // exit status 1
I have also tried replacing sh with /bin/bash.
I have also tried the following, with and without sh as the first argument:
out, err := exec.Command("tcpdump", "-i", "ens0", "host", "192.168.1.100", "-F", "./testfile").Output()
fmt.Println(string(out)) // Prints nothing
fmt.Println(err) // exit status 1
None of this is working. Can someone see what I am doing wrong? I have also tried this go package "github.com/kami-zh/go-capturer" to read stderr and again it prints nothing.
Normally I have to use sudo to execute tcpdump from shell, so I build the go binary and execute it as root user.
Something like this should work, i am not sure if there is any specific command like -F available in tcp dump,
If you want to capture plain output of the tcp dump , you can direct the output to file using > file . The -w option is for wireshark/tcpdump format , to read and display
cmd := exec.Command("sh", "-c", "sudo tcpdump -i <eth> host <ip> -w ./testfile")
err := cmd.Run()
if err != nil {
fmt.Println(err)
}
Thanks, #torek, the -c option can be used with tcpdump to exit after capturing n packets
cmd := exec.Command("sh", "-c", "sudo tcpdump -i ens33 -c 100 host localhost -w ./testfile")
err := cmd.Run()
if err != nil {
fmt.Println(err)
}
The other way is to use cmd.Start
cmd := exec.Command("sh", "-c", "sudo tcpdump -i ens33 -c 100 host localhost -w ./testfile")
err := cmd.Start()
if err != nil {
log.Fatal(err)
}
log.Printf("Waiting for command to finish...")
err = cmd.Wait()
log.Printf("Command finished with error: %v", err)
The tcpdump command continue to run infinitely if you use cmd.run without -c option with tcpdump cmd.So you can't see if you put print statement after cmd.Run() call, the reason being the exec.Command failed is, it just work the same way on how it works from the cli, so if you need sodo in front for it , you should put it in command as well or run it from the root user.
Trying to run terminal commands in Go using exec to get docker network usage but unable to. The following link shows how to get docker container's network usage using terminal and it works fine in terminal but not using Go. https://docs.docker.com/config/containers/runmetrics/
I get exit code 1, 2, 125, etc. with different combinations.
stdin, err := cmd.StdinPipe()
if err != nil {
log.Fatal(err)
}
defer stdin.Close()
io.WriteString(stdin, "CID="+CID) // container ID
io.WriteString(stdin,"TASKS=/sys/fs/cgroup/devices/docker/$CID*/tasks")
io.WriteString(stdin, "PID=$(head -n 1 $TASKS)")
io.WriteString(stdin, "mkdir -p /var/run/netns")
io.WriteString(stdin, "ln -sf /proc/$PID/ns/net /var/run/netns/$CID")
io.WriteString(stdin, "ip netns exec $CID netstat -i")
out, err := cmd.CombinedOutput()
if err != nil {
log.Fatal(err)
}
fmt.Printf("%s\n", out)
Expected output:
Kernel Interface table
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0 1450 1228323 0 0 0 1761314 0 0 0 BMRU
If someone looks for the same in the future, here's a working solution
cmd := exec.Command("/bin/sh", "-c", "CID="+CID+" ; TASKS=/sys/fs/cgroup/devices/docker/$CID*/tasks ; PID=$(head -n 1 $TASKS); mkdir -p /var/run/netns ; ln -sf /proc/$PID/ns/net /var/run/netns/$CID ; ip netns exec $CID netstat -i")
out, err := cmd.CombinedOutput()
if err != nil {
fmt.Println(err)
}
fmt.Printf("%s\n", out)
I am able to get the following command to open a new terminal and execute the command when I directly input it inside a terminal, but I can not get it to work when I use the exec.Commmand function in go.
osascript -e 'tell application "Terminal" to do script "echo hello"'
I think the issue lies within the double and single quotes, but I am not exactly sure what is causing the error.
c := exec.Command("osascript", "-e", "'tell", "application", `"Terminal"`, "to", "do", "script", `"echo`, `hello"'`)
if err := c.Run(); err != nil {
fmt.Println("Error: ", err)
}
As of now the code is returning Error: exit status 1, but I would like the code to open a terminal window and execute the command.
After playing some time found this:
cmd := exec.Command("osascript", "-s", "h", "-e",`tell application "Terminal" to do script "echo test"`)
Apparently you should give the automator script in 1 argument and also use ticks (`) as the string literals for go.
"-s", "h" is for automator program to tell you human readable errors.
My complete test code is as follows:
package main
import (
"fmt"
"os/exec"
"io/ioutil"
"log"
"os"
)
// this is a comment
func main() {
// osascript -e 'tell application "Terminal" to do script "echo hello"'
cmd := exec.Command(`osascript`, "-s", "h", "-e",`tell application "Terminal" to do script "echo test"`)
// cmd := exec.Command("sh", "-c", "echo stdout; echo 1>&2 stderr")
stderr, err := cmd.StderrPipe()
log.SetOutput(os.Stderr)
if err != nil {
log.Fatal(err)
}
if err := cmd.Start(); err != nil {
log.Fatal(err)
}
slurp, _ := ioutil.ReadAll(stderr)
fmt.Printf("%s\n", slurp)
if err := cmd.Wait(); err != nil {
log.Fatal(err)
}
}
PS: osascript is the command line interface for Automator app in macOS.
I've run into an issue with the os/exec library. I want to run a shell and pass it multiple commands to run, but it's failing when I do. Here's my test code:
package main
import (
"fmt"
"os/exec"
)
func main() {
fmt.Printf("-- Test 1 --\n`")
command1 := fmt.Sprintf("\"%s\"", "pwd") // this one succeeds
fmt.Printf("Running: %s\n", command1)
cmd1 := exec.Command("/bin/sh", "-c", command1)
output1,err1 := cmd1.CombinedOutput()
if err1 != nil {
fmt.Printf("error: %v\n", err1)
return
}
fmt.Printf(string(output1))
fmt.Printf("-- Test 2 --\n")
command2 := fmt.Sprintf("\"%s\"", "pwd && pwd") // this one fails
fmt.Printf("Running: %s\n", command2)
cmd2 := exec.Command("/bin/sh", "-c", command2)
output2,err2 := cmd2.CombinedOutput()
if err2 != nil {
fmt.Printf("error: %v\n", err2)
return
}
fmt.Printf(string(output2))
}
When running this I get an error 127 on the second example. It seems like it's looking for a literal "pwd && pwd" command instead of evaluating it as a script.
If I do the same thing from the command line it works just fine.
$ /bin/sh -c "pwd && pwd"
I'm using Go 1.4 on OS X 10.10.2.
the quotes are for your shell where you typed the command line, they should not be included when programatically launching an app
just make this change and it will work:
command2 := "pwd && pwd" // you don't want the extra quotes