> instead if you dont want to work with a real tab character. [:blank:] is > exactly space and tab.
These 3 methods are working: echo -e "\t 123" | grep -Eq "^[ | ]*123" && echo "real_tab" echo -e "\t 123" | grep -Eq "^[ |`echo -e "\t"`]*123" && echo "echo \\t" echo -e "\t 123" | grep -Eq "^[[:blank:]]*123" && echo "blank" _____ Tux
