Change default bash command for attaching the shell in Linux container.

Fixes #518 (#622)

commands/open-shell-container.ts

@@ -8,7 +8,6 @@ import { IActionContext } from 'vscode-azureextensionui';
 import { ContainerNode } from '../explorer/models/containerNode';
 import { RootNode } from '../explorer/models/rootNode';
 import { ext } from '../extensionVariables';
-import { reporter } from '../telemetry/telemetry';
 import { docker, DockerEngineType } from './utils/docker-endpoint';
 import { ContainerItem, quickPickContainer } from './utils/quick-pick-container';
 const teleCmdId: string = 'vscode-docker.container.open-shell';
@@ -17,9 +16,9 @@ function getEngineTypeShellCommands(engineType: DockerEngineType): string {
     const configOptions: vscode.WorkspaceConfiguration = vscode.workspace.getConfiguration('docker');
     switch (engineType) {
         case DockerEngineType.Linux:
-            return configOptions.get('attachShellCommand.linuxContainer', '/bin/sh');
+            return configOptions.get('attachShellCommand.linuxContainer');
         case DockerEngineType.Windows:
-            return configOptions.get('attachShellCommand.windowsContainer', 'powershell');
+            return configOptions.get('attachShellCommand.windowsContainer');
         default:
             throw new Error(`Unexpected engine type ${engineType}`);
     }

package.json

@@ -556,7 +556,7 @@
         },
         "docker.attachShellCommand.linuxContainer": {
           "type": "string",
-          "default": "/bin/bash",
+          "default": "/bin/sh -c \"[ -e /bin/bash ] && /bin/bash || /bin/sh\"",
           "description": "Attach command to use for Linux containers"
         },
         "docker.attachShellCommand.windowsContainer": {