Create utility framework for often used functions

utilities.sh

@@ -0,0 +1,84 @@
+#!/usr/bin/env bash
+
+### Utility functions to work with files
+file_exists() {
+  if [[ -f "$1" ]]; then
+    true
+  else
+    false
+  fi
+}
+# check for existence of pattern $2 in file $1
+line_exists() {
+  local file="$1"
+  local line="$2"
+
+  if ! file_exists "$file" || ! grep -qe "$line" "$file"; then
+    false
+  else
+    true
+  fi
+}
+# prepare newline at eof to make adding newlines easier
+eol_exists_or_append() {
+  local file="$1"
+  local eof
+  eof=$(tail -c 1 "$file")
+
+  if [ -n "$eof" ]; then
+    printf "\\n" >>"$file"
+  fi
+}
+# append line $2 to file $1
+line_exists_or_append() {
+  local file="$1"
+  local line="$2"
+  local new="${3:-$2}"
+
+  if ! line_exists "$file" "$line"; then
+    eol_exists_or_append "$file"
+    echo "$new" >>"$file"
+  fi
+}
+# Print a debug message to stdout
+dbg_msg() {
+  local application="$1"
+  shift
+
+  # the debug-level of the message
+  local level="$1"
+  local color
+  case "$level" in
+  error)
+    level=0
+    color="\u001b[31;1m"
+    shift
+    ;;
+  warn)
+    level=1
+    color="\u001b[33;1m"
+    shift
+    ;;
+  info)
+    level=2
+    color="\u001b[32;1m"
+    shift
+    ;;
+  *)
+    level=2
+    color="\u001b[32;1m"
+    ;;
+  esac
+
+  # the minimum debug level to display
+  local display=${STYLER_DEBUG:-"0"}
+  case "$display" in
+  error) display=0 ;;
+  warn) display=1 ;;
+  info) display=2 ;;
+  esac
+
+  if (("$level" <= "$display")); then
+    printf "%b%-15s %s \u001b[0m\n" "$color" "$(tr '[:lower:]' '[:upper:]' <<<\["$application"])" "$@"
+  fi
+}