some changes to mangaterm

.local/bin/mangaterm

@@ -1,4 +1,6 @@
-#!/bin/sh
+#!/bin/bash
+
+    set -e
 
 #using PID for dirname in case multiple instances are opened they do not interfere
 CACHEDIR="$HOME/.cache/mangaterm"
@@ -17,11 +19,14 @@ help() {
     echo "    mangaterm.sh DIRECTORY"
     echo "    mangaterm.sh FILE"
     echo ""
+    echo "    --help   show this help menu" 
+    echo ""
     echo "keybindings:"
     echo "    j -> next page"
     echo "    k -> previous page"
     echo "    q -> quit"
     echo ""
+    exit
 }
 
 disp() {
@@ -55,7 +60,6 @@ readDir() {
     disp "1"
 
     I=1
-    #TODO this read is bash specific
     while read_char char; do
         if [ "$char" = "j" ]; then
                 I=$((I + 1))
@@ -94,10 +98,53 @@ handleFile() {
 trap 'close' 2
 trap 'close' 15 
 
-mkdir -p "$TMPDIR"
 
-if [ "$(echo "$1" | cut -c1-1)" = "-" ]; then
-   foot -e mangaterm "$2" 2>/dev/null > /dev/null
+[ "$1" = "--help" ] && help
+
+if [ "$#" -gt 0 ]; then
+
+    mkdir -p "$TMPDIR"
+
+    if [ "$(echo "$1" | cut -c1-1)" = "-" ]; then
+       foot -e mangaterm "$2" 2>/dev/null > /dev/null
+    fi
+
+    handleFile "$1"
+else
+
+    LINES=()
+    
+    while IFS= read -r line; do
+        LINES+=("$line")
+    done
+
+    echo "${LINES[0]}"
+    echo "$I"
+
+    LEN="${#LINES[@]}"
+    I=0
+    while read -r -n 1 char < /dev/tty; do
+        if [ "$char" = "j" ]; then
+                I=$((I + 1))
+            elif [ "$char" = "k" ]; then
+                I=$((I - 1))
+            elif [ "$char" = "q" ]; then
+                close
+            fi
+
+        if [ "$I" -ge "$LEN" ] || [ "$I" -le "0" ]; then
+            if [ "$I" -ge "$LEN" ]; then
+                I="$LEN"
+            elif [ "$I" -lt "0" ]; then
+                I=0
+            fi 
+        fi
+
+        echo "${LINES["$I"]}"
+        echo "$I"
+    done
+
+    close
+
+
 fi
-
-handleFile "$1"