From a6e8585253899160fdf25300c91a22a1b5edfa4a Mon Sep 17 00:00:00 2001
From: Joursoir <chat@joursoir.net>
Date: Sat, 23 Jan 2021 12:38:54 +0000
Subject: add: work with stdin, determinate system bits, help

---
 spark.sh | 57 +++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 41 insertions(+), 16 deletions(-)

diff --git a/spark.sh b/spark.sh
index b7add42..ceac7b4 100755
--- a/spark.sh
+++ b/spark.sh
@@ -1,5 +1,33 @@
 #!/usr/bin/env bash
 
+function add_to_array() {
+	case $1 in
+		*[!0-9]*) exit 1 ;;
+		*) ;;
+	esac
+	array+=( $1 )
+
+	if [ $1 -gt $MAX ]; then
+		MAX=$1
+	fi
+	if [ $1 -lt $MIN ]; then
+		MIN=$1
+	fi
+}
+
+if [ -t 0 ] && [ $# -lt 2 ] || [ "$1" = "-h" ] || [ "$1" = "--help" ]
+then
+	cat <<-EOF
+		Spark
+
+		Code was written by Joursoir <chat@joursoir.net>
+		This is free and unencumbered software released into the public domain.
+
+		Synopsis: spark [number] [number] [number] ...
+		EOF
+	exit 0
+fi
+
 case `uname -m` in
 	x86_64|amd64) # 64 bit
 		MAX=$(( -2**63 ));
@@ -12,29 +40,26 @@ case `uname -m` in
 		MIN=$(( 2*15-1 )) ;;
 esac
 
-for i in "$@"
-do
-	case $i in
-		''|*[!0-9]*) exit 1 ;;
-		*) ;;
-	esac
-
-	if [ $i -gt $MAX ]; then
-		MAX=$i
-	fi
-	if [ $i -lt $MIN ]; then
-		MIN=$i
-	fi
-done
+if [ $# -gt 1 ]
+then
+	for i in "$@"; do
+		add_to_array $i
+	done
+else
+	while read -r i; do
+		add_to_array $i
+	done
+fi
 
 LEVELS=8
 DIFF=$(( $MAX - $MIN + 1 ))
 
-for i in "$@"
+for i in "${array[@]}"
 do
 	H=$(( 1 + ($i - $MIN + 1) * ($LEVELS-1) / $DIFF ))
 
 	printf "\u258$H"
 done
 
-echo
\ No newline at end of file
+echo
+exit 0
\ No newline at end of file
-- 
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