add pip command and fix error codes on all commands

cmd/node.go

@@ -25,13 +25,9 @@ func Node(args ...string) (output string, err error) {
 	if err != nil {
 		var exitErr *exec.ExitError
 		if errors.As(err, &exitErr) {
-			if exitErr.ExitCode() == 1 {
-				return "", ErrNotFound
-			} else {
 			return "", fmt.Errorf("command error: %w", err)
 		}
 	}
-	}
 
 	return strings.Trim(string(outputBytes), "\n"), nil
 

cmd/pip.go

@@ -0,0 +1,33 @@
+package cmd
+
+import (
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+func Pip(args ...string) (output string, err error) {
+
+	if _, err := Which("python3"); err != nil {
+		if errors.Is(err, ErrNotFound) {
+			return "", PythonNotFound
+		} else {
+			return "", err
+		}
+	}
+
+	command := exec.Command("python3", "-m", "pip")
+	command.Args = append(command.Args, args...)
+
+	outputBytes, err := command.Output()
+	if err != nil {
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			return "", fmt.Errorf("command error: %w", err)
+		}
+	}
+
+	return strings.Trim(string(outputBytes), "\n"), nil
+
+}

cmd/python.go

@@ -25,13 +25,9 @@ func Python(args ...string) (output string, err error) {
 	if err != nil {
 		var exitErr *exec.ExitError
 		if errors.As(err, &exitErr) {
-			if exitErr.ExitCode() == 1 {
-				return "", ErrNotFound
-			} else {
 			return "", fmt.Errorf("command error: %w", err)
 		}
 	}
-	}
 
 	return strings.Trim(string(outputBytes), "\n"), nil