video.sh

#!/usr/bin/env bash

declare RED="\e[0;31m"
declare GRN="\e[0;32m"
declare CRESET="\e[0m"

declare -a commands
declare -a descriptions

trap "exec 7<&-; echo 'Bye...'" EXIT
#it's just an end clap

next_instruction(){
	local tmp_var

	if [ "$manual_skip" -eq 0 ]
	then
		sleep "$1"
	else
		read -s -r -n 1 -u 7
	fi
}

print_command(){
	local command="$1"
	local description="$2"
	local prompt=">>>"

	if [ "$description" != "" ] ; then echo "#$description" ; fi
	printf "%b\n" "${GRN}$prompt${CRESET}$command"
	next_instruction "$timer"
}

print_and_run(){
	local command="$1"
	local description="$2"
	local -i printable=1

	if [ "$command" = "" ]; then command=":"; fi
	if [ "$description" = "" ]; then description="" ; fi
	clear
	if [ "${command:0:1}" != "@" ] ; then print_command "$command" "$description"
	else command="${command:1}" ; printable=0; fi
	if ! eval "$command" ; then return 1; fi
	if [ "$printable" -eq "1" ] ; then
	next_instruction "$timer" ; fi
}

run_commands_files(){
	declare	command
	declare description
	declare commands_file="$1"
	declare descriptions_file="$2"
	declare	tmp_file

	if [ "$commands_file" == "" ] ; then echo "Please provide at least a commands file "; exit 1; fi
	tmp_file="$(mktemp)"
	paste "$commands_file" "$descriptions_file" > "$tmp_file"
	while IFS=$'\t' read -r -u 6 command description
		do if ! print_and_run "$command" "$description"; then printf "%b\n" "Error while running : ${RED}$command${CRESET}" ; rm "$tmp_file" ; exit 1; fi
	done 6<"$tmp_file"
	rm "$tmp_file"
}

run_commands_file(){
	declare	command
	declare description
	declare	commands_file="$1"

	if [ "$commands_file" == "" ] ; then echo "Please provide at least a commands file "; exit 1; fi
	while IFS="$separator" read -r -u 6 command description
	do
		if ! print_and_run "$command" "$description"; then printf "%b\n" "Error while running : ${RED}$command${CRESET}" ; exit 1; fi
	done 6<"$commands_file"
}

run_commands_arrays(){
	for (( i = 0; i<${#commands[@]}; ++i ))
	do if ! print_and_run "${commands[$i]}" "${descriptions[$i]}"; then printf "%b\n" "Error while running : ${RED}${commands[$i]}${CRESET}"; exit 1; fi
	done
}

:<<-PARSE_OPTIONS
	Function that allows the parsing of the programm options using the getopts (and not getopt) POSIX utility
	PARSE_OPTIONS
parse_options(){
	declare optstring="s:mt:h"
	declare	option

	while getopts "$optstring" option; do
	case "$option" in
		s)
			separator="$OPTARG";;
		m)
			if [ "$manual_skip" -eq "0" ] ; then manual_skip=1 ; fi ;;
		t)
			if [ "$manual_skip" -eq "0" ] ; then timer="$OPTARG"; fi;;
		h)
			help ; exit 0 ;;
		?)
			echo "Usage: ${0}: [-s separator] [-m] [-t time] [commands_file [descriptions_file]]"; exit 2;;
	esac
	done
}

help(){
	cat <<"HELP"
Please either fill the commands and descriptions array in the script
or run the script providing a commands_file and a descriptions_file
You can specify commands that won't be printed (nor their descriptions)
by prefixing the line with a '@'
The default separator for a file that contains the command alongside their descriptions on the same line is '|'
However, you can change this setting using the option -s separator.
For example, the command `./video.sh -s a commands_file` will use 'a' as a separator.
While the command `./video.sh -s $'\t' command_file` will use the tab character as a separator.
Running the script with the option '-m' will allow you to manually skip to the next instruction, instead of waiting for a timer
Running the script with the option '-t' followed by a time (in seconds) will set the timer for the next instruction to the number
of seconds specified on the command line, however any -m option will override any timer set in the script options
-You can run the script this way :
	./video.sh [-s separator] [-m] [-t time]  commands_file descriptions_file
	./video.sh [-s separator] [-m] commands_file (with commands and descriptions separated by a '|' symbol)
	./video.sh [-s separator] [-m] [-t time]
Note: you can run :
bash <(curl -fsSL --connect-timeout 10 https://raw.githubusercontent.com/nsainton/man_reader/master/man_reader.sh || echo "echo man_reader couldn\'t be retrieved, exiting; exit 1") bash "QUOTING"
to get more info about the construct : "$'character'"
HELP
}

main(){
	declare commands_file
	declare	descriptions_file
	#separator may be used in the parse_options function
	# shellcheck disable=SC2034
	declare separator="|"
	declare	-i timer=5
	declare	-i manual_skip=0

	exec 7</dev/tty
	parse_options "$@"
	shift $((OPTIND - 1))
	commands_file="$1"
	descriptions_file="$2"
	if [ "$commands_file" != "" ] && [ "$descriptions_file" != "" ] ; then run_commands_files "$commands_file" "$descriptions_file";  exit 0 ; fi
	if [ "$commands_file" != "" ] ; then run_commands_file "$commands_file"; exit 0; fi
	if [ "${#commands[@]}" -gt "0" ] ; then run_commands_arrays; exit 0 ; fi
	help
	exit 1
}

main "$@"