ghacks-user.js updater for Mac/Linux v1.3 (#406)

* updated shebang

* The script now compares its version number to the one online.  If there is a newer version of `updater.sh` online it ask the user if he wants to download and run it.
   * 2 parameters are supported: `-donotupdate` to disable the update-check and `-update` to auto-download and run the new version without asking

* Backup files are now saved to the directory `userjs_backups` instead of causing more bloat in the profile directory.

updater.sh

@@ -1,12 +1,14 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 ### ghacks-user.js updater for Mac/Linux
 ## author: @overdodactyl
-## version: 1.2
+## version: 1.3
 
-ghacksjs="https://raw.githubusercontent.com/ghacksuserjs/ghacks-user.js/master/user.js"
+## DON'T GO HIGHER THAN VERSION x.9 !! ( because of ASCII comparison in check_for_update() )
 
-echo -e "\nThis script should be run from your Firefox profile directory.\n"
+ghacksjs="https://raw.githubusercontent.com/ghacksuserjs/ghacks-user.js/master/user.js"
+updater="https://raw.githubusercontent.com/ghacksuserjs/ghacks-user.js/master/updater.sh"
+update_pref=${1:--ask}
 
 currdir=$(pwd)
 
@@ -19,40 +21,99 @@ if [ -z "$sfp" ]; then sfp=${BASH_SOURCE[0]}; fi
 ## change directory to the Firefox profile directory
 cd "$(dirname "${sfp}")"
 
-echo -e "Updating the user.js for Firefox profile:\n$(pwd)\n"
+## Used to check if a new version of updater.sh is available
+update_available="no"
+check_for_update () {
+  online_version="$(curl -s ${updater} | sed -n '5 s/.*[[:blank:]]\([[:digit:]]*\.[[:digit:]]*\)/\1/p')"
+  path_to_script="$(dirname "${sfp}")/updater.sh"
+  current_version="$(sed -n '5 s/.*[[:blank:]]\([[:digit:]]*\.[[:digit:]]*\)/\1/p' "$path_to_script")"
+  if [[ "$current_version" < "$online_version" ]]; then
+    update_available="yes"
+  fi
+}
+
+## Used to backup the current script, and download and execute the latest version of updater.sh
+update_script () {
+  echo -e "This script will be backed up and the latest version of updater.sh will be executed.\n"
+  mv updater.sh "updater.sh.backup.$(date +"%Y-%m-%d_%H%M")"
+  curl -O ${updater} && echo -e "\nThe latest updater script has been downloaded\n"
+  
+  # make new file executable
+  chmod +x updater.sh
+
+  # execute new updater script
+  ./updater.sh -donotupdate
+
+  # exit script
+  exit 1
+}
 
-if [ -e user.js ]; then
-  echo "Your current user.js file for this profile will be backed up and the latest ghacks version from github will take its place."
-  echo -e "\nIf currently using the ghacks user.js, please compare versions:"
-  echo "  Available online: $(curl -s ${ghacksjs} | sed -n '4p')"
-  echo "  Currently using:  $(sed -n '4p' user.js)"
-else
-  echo "A user.js file does not exist in this profile. If you continue, the latest ghacks version from github will be downloaded."
-fi
 
-echo -e "\nIf a user-overrides.js file exists in this profile, it will be appended to the user.js.\n"
+main () {
+  ## create backup folder if it doesn't exist
+  mkdir -p userjs_backups;
 
-read -p "Continue Y/N? " -n 1 -r
-echo -e "\n\n"
+  echo -e "\nThis script should be run from your Firefox profile directory.\n"
+
+  echo -e "Updating the user.js for Firefox profile:\n$(pwd)\n"
 
-if [[ $REPLY =~ ^[Yy]$ ]]; then
   if [ -e user.js ]; then
-    # backup current user.js
-    bakfile="user.js.backup.$(date +"%Y-%m-%d_%H%M")"
-    mv user.js "${bakfile}" && echo "Your previous user.js file was backed up: ${bakfile}"
+    echo "Your current user.js file for this profile will be backed up and the latest ghacks version from github will take its place."
+    echo -e "\nIf currently using the ghacks user.js, please compare versions:"
+    echo "  Available online: $(curl -s ${ghacksjs} | sed -n '4p')"
+    echo "  Currently using:  $(sed -n '4p' user.js)"
+  else
+    echo "A user.js file does not exist in this profile. If you continue, the latest ghacks version from github will be downloaded."
   fi
 
-  # download latest ghacks user.js
-  echo "downloading latest ghacks user.js file"
-  curl -O ${ghacksjs} && echo "ghacks user.js has been downloaded"
+  echo -e "\nIf a user-overrides.js file exists in this profile, it will be appended to the user.js.\n"
+
+  read -p "Continue Y/N? " -n 1 -r
+  echo -e "\n\n"
+
+  if [[ $REPLY =~ ^[Yy]$ ]]; then
+    if [ -e user.js ]; then
+      # backup current user.js
+      bakfile="userjs_backups/user.js.backup.$(date +"%Y-%m-%d_%H%M")"
+      mv user.js "${bakfile}" && echo "Your previous user.js file was backed up: ${bakfile}"
+    fi
+
+    # download latest ghacks user.js
+    echo "downloading latest ghacks user.js file"
+    curl -O ${ghacksjs} && echo "ghacks user.js has been downloaded"
 
-  if [ -e user-overrides.js ]; then
-    echo "user-overrides.js file found"
-    cat user-overrides.js >> user.js && echo "user-overrides.js has been appended to user.js"
+    if [ -e user-overrides.js ]; then
+      echo "user-overrides.js file found"
+      cat user-overrides.js >> user.js && echo "user-overrides.js has been appended to user.js"
+    fi
+  else
+    echo "Process aborted"
   fi
+
+  ## change directory back to the original working directory
+  cd "${currdir}"
+}
+
+update_pref="$(echo $update_pref | tr '[A-Z]' '[a-z]')"
+if [ $update_pref = "-donotupdate" ]; then
+  main
 else
-  echo "Process aborted"
+  check_for_update
+  if [ $update_available = "no" ]; then
+    main
+  else
+    ## there is an update available 
+    if [ $update_pref = "-update" ]; then
+      ## update without asking
+      update_script
+    else 
+      read -p "There is a newer version of updater.sh available.  Download and execute?  Y/N? " -n 1 -r
+      echo -e "\n\n"
+      if [[ $REPLY =~ ^[Yy]$ ]]; then
+        update_script
+      else
+        main
+      fi
+    fi
+  fi
 fi
-
-## change directory back to the original working directory
-cd "${currdir}"