feat(better-cat): add solution for exercise

sh/tests/solutions/better-cat.sh

@@ -0,0 +1,51 @@
+#!/bin/bash
+
+while getopts "clr" opt; do
+  case $opt in
+    c) exclude_comments=true;;
+    l) show_length=true;;
+    r) show_recap=true;;
+    *) echo "Usage: $0 [-c] [-l] [-r] [file1] [file2] ..." >&2
+       exit 1;;
+  esac
+done
+
+shift $((OPTIND-1))
+
+if [[ $# -eq 0 ]]; then
+  set -- *
+fi
+
+line_count=0
+char_count=0
+
+for file in "$@"; do
+  if [[ ! -e $file ]]; then
+    echo "$0: $file: No such file or directory" >&2
+    continue
+  fi
+  
+  line_num=0
+  while read -r line; do
+    line_num=$((line_num+1))
+    if [[ $exclude_comments && $line == \#* ]]; then
+      continue
+    fi
+    if [[ $show_length ]]; then
+      echo "$line_num ($(( ${#line} ))): $line"
+    else
+      echo "$line_num: $line"
+    fi
+    char_count=$((char_count+${#line}))
+  done < "$file"
+  
+  line_count=$((line_count+line_num))
+done
+
+if [[ $show_recap ]]; then
+  echo "Total: $line_count lines, $char_count characters"
+fi
+
+if [[ $line_count -eq 0 ]]; then
+  exit 1
+fi