diff --git a/shell-functions b/shell-functions
index a44eba1..0e53937 100644
--- a/shell-functions
+++ b/shell-functions
@@ -20,23 +20,5 @@ function print_error_noisy { [ ${NOISY:-0} -ge $1 ] && print_error $@[2,-1] }
 function print_info_sub_noisy { [ ${NOISY:-0} -ge $1 ] && print_info_sub $@[2,-1] }
 function print_error_sub_noisy { [ ${NOISY:-0} -ge $1 ] && print_error_sub $@[2,-1] }
 
-# Return 1 if the binary exists (according to hash); 0 otherwise.
-function binary_exists {
-    hash $1 &>/dev/null
-    if [[ $? ]]; then
-        return 1
-    else
-        return 0
-    fi
-}
-
-# Return 1 if the binary doesn't exist (according to hash); 0 otherwise. See
-# binary_exists.
-function binary_not_exists {
-    binary_exists $1 &>/dev/null
-    if [[ $? ]]; then
-        return 0
-    else
-        return 1
-    fi
-}
+function binary_exists { return $(hash $1 1>/dev/null 2>&1) }
+function binary_not_exists { binary_exists $1; return $(( ! $? )) }