update: zsh performance tracer

Author: Esonhugh

zsh_preformance_tracer.sh

@@ -0,0 +1,28 @@
+zsh_trace_start() {
+    echo "starting zsh tracing"
+    # set the trace prompt to include seconds, nanoseconds, script name and line number
+    # This is GNU date syntax; by default Macs ship with the BSD date program, which isn't compatible
+    if [[ $ZSH_VERSION > 4.3.11 ]]; then
+        zmodload zsh/datetime
+        setopt promptsubst
+        export PS4='+$EPOCHREALTIME %N:%i> '
+    else
+        export PS4='+$(date "+%s:%N") %N:%i> '
+    fi
+    # save file stderr to file descriptor 3 and redirect stderr (including trace 
+    # output) to a file with the script's PID as an extension
+    exec 3>&2 2>/tmp/startlog.$$
+    # set options to turn on tracing and expansion of commands contained in the prompt
+    setopt xtrace prompt_subst
+    trap 'setopt xtrace' EXIT
+}
+
+zsh_trace_end() {
+    # turn off tracing
+    unsetopt xtrace
+    # restore stderr to the value saved in FD 3
+    exec 2>&3 3>&-
+    echo "zsh tracing done. See /tmp/startlog.$$"
+    trap 'unsetopt xtrace' EXIT
+}
+