Generate a markdown file that presents a table grid of all PNG images in the current directory,

markdown_gen.sh

#!/bin/bash

md_filename="vis.md"
cnt=0

echo "| | | | |" >> $md_filename
echo "|-|-|-|-|" >> $md_filename
for file in $(ls | grep png)
do
   printf "| ![$file](./$file) 
 $file" >> $md_filename;
   if [ $(($cnt%4)) -eq 3 ];
     then
     printf "|\n" >> $md_filename;
   fi;
   let cnt=cnt+1;
done