1 files changed, 40 insertions, 0 deletions
diff --git a/oh-my-zsh.sh b/oh-my-zsh.sh
index 545d980f0..b388b341d 100644
--- a/oh-my-zsh.sh
+++ b/oh-my-zsh.sh
@@ -1,3 +1,43 @@
+# Protect against non-zsh execution of Oh My Zsh (use POSIX syntax here)
+[ -n "$ZSH_VERSION" ] || {
+  # ANSI formatting function (\033[<code>m)
+  # 0: reset, 1: bold, 4: underline, 22: no bold, 24: no underline, 31: red, 33: yellow
+  omz_f() {
+    [ $# -gt 0 ] || return
+    IFS=";" printf "\033[%sm" $*
+  }
+  # If stdout is not a terminal ignore all formatting
+  [ -t 1 ] || omz_f() { :; }
+
+  omz_ptree() {
+    # Get process tree of the current process
+    pid=$$; pids="$pid"
+    while [ ${pid-0} -ne 1 ] && ppid=$(ps -e -o pid,ppid | awk "\$1 == $pid { print \$2 }"); do
+      pids="$pids $pid"; pid=$ppid
+    done
+
+    # Show process tree
+    case "$(uname)" in
+    Linux) ps -o ppid,pid,command -f -p $pids 2>/dev/null ;;
+    Darwin|*) ps -o ppid,pid,command -p $pids 2>/dev/null ;;
+    esac
+
+    # If ps command failed, try Busybox ps
+    [ $? -eq 0 ] || ps -o ppid,pid,comm | awk "NR == 1 || index(\"$pids\", \$2) != 0"
+  }
+
+  {
+    shell=$(ps -o pid,comm | awk "\$1 == $$ { print \$2 }")
+    printf "$(omz_f 1 31)Error:$(omz_f 22) Oh My Zsh can't be loaded from: $(omz_f 1)${shell}$(omz_f 22). "
+    printf "You need to run $(omz_f 1)zsh$(omz_f 22) instead.$(omz_f 0)\n"
+    printf "$(omz_f 33)Here's the process tree:$(omz_f 22)\n\n"
+    omz_ptree
+    printf "$(omz_f 0)\n"
+  } >&2
+
+  return 1
+}
+
 # If ZSH is not defined, use the current script's directory.
 [[ -z "$ZSH" ]] && export ZSH="${${(%):-%x}:a:h}"