There's a typo, the one liner should read:
for gnome_autostart in $(awk '/^OnlyShowIn=/ && /GNOME;/ && !/XFCE;/ { print FILENAME }' /etc/xdg/autostart/*); do sed '$aHidden=true' ${gnome_autostart} >${HOME}/.config/autostart/${gnome_autostart##*/}; done
There's a typo, the one liner should read:
for gnome_autostart in $(awk '/^OnlyShowIn=/ && /GNOME;/ && !/XFCE;/ { print autostart/ *); do sed '$aHidden=true' ${gnome_autostart} /.config/ autostart/ ${gnome_ autostart# #*/}; done
FILENAME }' /etc/xdg/
>${HOME}