How does one choose between `"$0"` and `"${BASH_SOURCE[0]}"` This description from [GNU][1] didn't help me much. BASH_SOURCE An array variable whose members are the source filenames where the corresponding shell function names in the FUNCNAME array variable are defined. The shell function ${FUNCNAME[$i]} is defined in the file ${BASH_SOURCE[$i]} and called from ${BASH_SOURCE[$i+1]} [1]: https://www.gnu.org/software/bash/manual/html_node/Bash-Variables.html#Bash-Variables