Question

I’ve written a small library function to help me exit when the script owner isn’t root:

#!/bin/bash   

# Exit for non-root user

exit_if_not_root() {
        if [ "$(id -u)" == "0" ]; then return; fi
        if [ -n "$1" ];
        then
                printf "%s" "$1"
        else
                printf "Only root should execute This script. Exiting now.\n"
        fi
        exit 1
}

Here I call it from another file:

#!/bin/bash

source ../bashgimp.sh

exit_if_not_root "I strike quickly, being moved. But thou art not quickly moved to strike.\n You're not root, exiting with custom message."

And the output is:

I strike quickly, being moved. But thou art not quickly moved to strike.\n You're not root, exiting with custom message.

How can I get the newline to appear correctly?

Answer 1

Maybe do away with the "%s" and just

printf "$1"

would be simplest in this case.

ANSI-C escape sequences are not treated as such by default in strings – they are the same as other literals. The form

$'ANSI text here'

will undergo backslash-escape replacement though. (Ref.)

In your case though, as you’re just printing the formatted string provided, you may as well treat it as the format string rather than an argument.