Improve Xtrace by hiding output of prompt commands

bash/.bashrc

@@ -116,6 +116,23 @@ if [ -f "$HOME/.private_functions" ] && [ -r "$HOME/.private_functions" ]; then
   . "$HOME/.private_functions"
 fi
 
+# Preserve the usefulness of set -x by attempting to hide everything that
+# happens in prompt_command
+preserve_xtrace() {
+  if grep -q "x" <<< $-; then
+    XTRACE_WAS_SET=1
+    set +x
+  fi
+} 2>/dev/null
+preserve_xtrace_reset() {
+  if [ "${XTRACE_WAS_SET}" ]; then
+    set -x
+    unset XTRACE_WAS_SET
+  fi
+} 2>/dev/null
+
+PROMPT_COMMAND="preserve_xtrace; $PROMPT_COMMAND; preserve_xtrace_reset"
+
 if $(which direnv &> /dev/null); then
   eval "$(direnv hook bash)"
 fi