check shell via basename

#refs 124
#refs 123

src/app.exec.ts

@@ -245,8 +245,8 @@ async function abracadabra(opts: Args): Promise<RV> {
 
     //FIXME putting "$@" at the end can be invalid, it really depends on the script TBH
     //FIXME shouldn’t necessarily default to bash
-    
-    // This is short term until a longer term fix is available through a deno library 
+
+    // This is short term until a longer term fix is available through a deno library
     const saferArg0 = arg0 === '.' ? 'sh' : arg0.replaceAll('../', '')
 
     const path = Path.mktmp().join(saferArg0).write({ force: true, text: undent`
@@ -294,8 +294,8 @@ async function repl(installations: Installation[], env: Record<string, string>)
   const shell = Deno.env.get("SHELL")?.trim() || "/bin/sh"
   const cmd = [shell, '-i'] // interactive
 
-  //TODO other shells pls
-  if (shell == '/bin/zsh') {
+  //TODO other shells pls #help-wanted
+  if (Path.abs(shell)?.basename() == 'zsh') {
     env['PS1'] = "%F{086}tea%F{reset} %~ "
     cmd.push('--no-rcs', '--no-globalrcs')
   }

src/vendor/Path.ts

@@ -49,6 +49,15 @@ export default class Path {
     }
   }
 
+  /// returns Path | undefined rather than throwing error if Path is not absolute
+  static abs(input: string | Path) {
+    try {
+      return new Path(input)
+    } catch {
+      return
+    }
+  }
+
   /**
     If the path represents an actual entry that is a symlink, returns the symlink’s
     absolute destination.