autoselect tmux

terminus-terminal/src/index.ts

@@ -48,7 +48,12 @@ import { hterm } from './hterm'
                 if (hostApp.platform === Platform.Windows) {
                     return null
                 } else {
-                    return tmux
+                    if (tmux.isAvailable()) {
+                        tmux.init()
+                        return tmux
+                    } else {
+                        return screen
+                    }
                 }
             },
             deps: [HostAppService, ScreenPersistenceProvider, TMuxPersistenceProvider],

terminus-terminal/src/tmux.ts

 import { Injectable } from '@angular/core'
+import { execFileSync } from 'child_process'
 import * as AsyncLock from 'async-lock'
 import { ConnectableObservable, Subject } from 'rxjs'
 import * as childProcess from 'child_process'
@@ -166,6 +167,18 @@ export class TMuxPersistenceProvider extends SessionPersistenceProvider {
 
     constructor () {
         super()
+    }
+
+    isAvailable (): boolean {
+        try {
+            execFileSync('tmux', ['-V'])
+            return true
+        } catch (_) {
+            return false
+        }
+    }
+
+    init () {
         this.tmux = new TMux()
     }