custom-shell-scripts/strSlice at main · jmortiger/custom-shell-scripts · GitHub

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#!/usr/bin/env bash

if [ "$1" = '--help' ]; then
	exit 1
elif [ "$1" = '--version' ]; then
	exit 1
fi

# TODO: Inclusive/exclusive flags

# declare -i start
# declare -i end
# declare string
# shopt -s extglob globasciiranges
# while (($# > 0)); do
# 	case "$1" in
# 		^-?[[:digit:]]+$)
# 			if [ -n "$start" ]; then
# 				if [ -n "$end" ]; then
# 					string+="$1"
# 				else
# 					end="$1"
# 				fi
# 			else
# 				start="$1"
# 			fi
# 			;;
# 		*)
# 			string+="$1"
# 			;;
# 	esac
# 	shift
# done
declare -i start=0
declare -i end
declare string
shopt -s extglob globasciiranges
if [[ "$1" =~ ^-?[[:digit:]]+$ ]]; then
	((start = $1))
	shift
else
	exit 1
fi
if [ "$1" = '--' ]; then
	unset end
	shift
elif [[ "$1" =~ ^-?[[:digit:]]+$ ]]; then
	((end = $1))
	declare -r end
	shift
else
	unset end
fi
declare -r start string="$*"
# TODO: Option to enable escape sequences
if [ -z "$end" ]; then
	echo -nE "${string: $start}"
else
	echo -nE "${string: $start:$end}"
fi
exit