Adding some Go bits, correcting some warts

plus getting to the bottom of shell startup slowness, which appears to
be almost entirely due to rbenv.

bash_aliases

@@ -1,3 +1,5 @@
+#!/bin/bash
+
 alias .bp="source $HOME/.bash_profile"
 alias .sa="source $HOME/.ssh/agent.out"
 alias be='bundle exec'
@@ -15,12 +17,13 @@ alias sS='TERM=xterm screen -Rd -S '
 alias scr='TERM=xterm screen -Rd'
 alias sl="screen -ls"
 
-if [[ "$(uname)" -eq "Linux" ]]
-then
-    alias l='ls -F --color=auto'
-else
-    # for darwin in particular
-    alias l='ls -GF'
-fi
+case "$(uname | tr '[:upper:]' '[:lower:]')" in
+    darwin)
+        alias l='ls -GF'
+        ;;
+    *)
+        alias l='ls -F --color=auto'
+        ;;
+esac
 
 # vim:filetype=sh