Use 'read' built-in instead of $(cat ... | head -n1)

nvm.sh

@@ -74,7 +74,7 @@ nvm_rc_version() {
   local NVMRC_PATH
   NVMRC_PATH="$(nvm_find_nvmrc)"
   if [ -e "$NVMRC_PATH" ]; then
-    NVM_RC_VERSION=`cat "$NVMRC_PATH" | head -n 1`
+    read NVM_RC_VERSION < "$NVMRC_PATH"
     echo "Found '$NVMRC_PATH' with version <$NVM_RC_VERSION>"
   fi
 }