For example, in your bash shell script you`re going to use some root-specific commands like network operations, mounting devices and so on. There are couple easy ways to check if your script is executing under root privileges.
#!/bin/bash # ... if [ "$(id -u)" != "0" ]; then echo "This script must be run as root" 1>&2 exit 1 fi # ...
Another way: use EUID. When user account created a user ID is assigned to each user. Bash shell stores the user ID in $UID variable. Your effective user ID is stored in $EUID variable.
#!/bin/bash # ... if [[ $EUID -ne 0 ]]; then echo "This script must be run as root" 1>&2 exit 1 fi # ...
