Determine the root user in linux

In linux, how does one determine whether the current user is root? Determine whether the current user is root www.2cto.com Shell code Java code # ------------------------------ root user check --------------------- start if ['id-U'-ne 0]; then echo "Please re-run $ {this_file} as root. "exit 1 fi # ------------------------------ root user check ------------------- end if [x" $ USER "= x" "]; then if id | grep" ^ uid = 0 (root) ">/dev/null; then: else echo" Please rerun 'basename $ 0' as root. "exit 1 fi els E if [! X "$ USER" = x "root"]; then echo "Please rerun 'basename $ 0' as root. "exit 1 fi #==================== check current user start ======================== = if [! $ USER = root]; then echo "Please rerun this script as root. "exit 1 fi #===================== check current user end ============================ #! /Bin/sh if id | grep "^ uid = 0 (root)">/dev/null; then echo is root else echo not root fi check_user () {if [$ UID-ne 0]; then echo "Current user is not ROOT. "echo" Please rerun the installer as Root user. "exit 11 fi}