diff --git a/themes/agnoster/agnoster.theme.sh b/themes/agnoster/agnoster.theme.sh
index ebcd4c7..b1eb2d3 100755
--- a/themes/agnoster/agnoster.theme.sh
+++ b/themes/agnoster/agnoster.theme.sh
@@ -249,7 +249,7 @@ git_status_dirty() {
 # Git: branch/detached head, dirty status
 prompt_git() {
     local ref dirty
-    if $(git rev-parse --is-inside-work-tree >/dev/null 2>&1); then
+    if git rev-parse --is-inside-work-tree &>/dev/null; then
         ZSH_THEME_GIT_PROMPT_DIRTY='±'
         dirty=$(git_status_dirty)
         ref=$(git symbolic-ref HEAD 2> /dev/null) || ref="➦ $(git show-ref --head -s --abbrev |head -n1 2> /dev/null)"
diff --git a/themes/rana/rana.theme.sh b/themes/rana/rana.theme.sh
index ab1d660..5ab804e 100644
--- a/themes/rana/rana.theme.sh
+++ b/themes/rana/rana.theme.sh
@@ -137,12 +137,12 @@ prompt_git() {
 			git update-index --really-refresh -q &>/dev/null;
 
 			# Check for uncommitted changes in the index.
-			if ! $(git diff --quiet --ignore-submodules --cached); then
+			if ! git diff --quiet --ignore-submodules --cached; then
 				s+='+';
 			fi;
 
 			# Check for unstaged changes.
-			if ! $(git diff-files --quiet --ignore-submodules --); then
+			if ! git diff-files --quiet --ignore-submodules --; then
 				s+='!';
 			fi;
 
@@ -152,7 +152,7 @@ prompt_git() {
 			fi;
 
 			# Check for stashed files.
-			if $(git rev-parse --verify refs/stash &>/dev/null); then
+			if git rev-parse --verify refs/stash &>/dev/null; then
 				s+='$';
 			fi;
 
diff --git a/themes/rjorgenson/rjorgenson.theme.sh b/themes/rjorgenson/rjorgenson.theme.sh
index 2375657..a0635ce 100644
--- a/themes/rjorgenson/rjorgenson.theme.sh
+++ b/themes/rjorgenson/rjorgenson.theme.sh
@@ -49,7 +49,7 @@ function is_integer() { # helper function for todo-txt-count
 }
 
 todo_txt_count() {
-    if `hash todo.sh 2>&-`; then # is todo.sh installed
+    if _omb_util_command_exists todo.sh; then # is todo.sh installed
         count=$(todo.sh ls | egrep "TODO: [0-9]+ of ([0-9]+) tasks shown" | awk '{ print $4 }')
         if is_integer $count; then # did we get a sane answer back
             echo "${BRACKET_COLOR}[${STRING_COLOR}T:$count${BRACKET_COLOR}]$normal"