Bash function to read the lines of a file into an array using the builtin, mapfile.

fileLines2Array.sh

#!/bin/bash
### Pretty-print dedicated (array) var, MAPFILE.
prettyPrintMAPFILE() {
	let i=0
	echo "[MAPFILE]"
	for l in "${MAPFILE[@]}"
	do
		echo "$i.   |$l|"
		let i++
	done
	echo "[/MAPFILE]"
}

### Read the lines of the specified file into an array.
##		Skips blank lines. Trims leading & trailing spaces in every line.
##		Resulting array is in the dedicated var, MAPFILE.
##	Params:
##		1.	File location to be read (required).
##		2.	Comment delimiter (optional; default: '#').
##+			-- to delimit any text that is to be omitted. 
fileLines2Array() {
	if [[ -z "$1" ]] || [[ ! -e $1 ]]; then
		echo "File not provided or does not exist."
		return 1
	else
		echo "File to read: $1"
	fi

	commentPattern="\#*"
	[[ -n "$2" ]] && commentPattern="\\$2*"
	[[ -n "$commentPattern" ]] && echo "  ... will skip lines and trailing portions of lines beginning with this pattern: '$commentPattern'."

	mapfile -t < $1
	
	let i=0
	for l in "${MAPFILE[@]}"
	do
		l=${l%%$commentPattern}		# Remove trailing portion beginning with delimiter.
		l=${l%%*( )}				# Trim trailing spaces
		l=${l##*( )}				# Trim leading spaces
		if [[ -z "$l" ]]; then		# Remove line if it is empty/blank.
			unset MAPFILE[$i]
		else
			MAPFILE[$i]=$l			# Replace the line we read with its modified version.
		fi
		let i++
	done
	
	prettyPrintMAPFILE

	return 0
}