Clean up git-prune-branches

* Quote bare variables
* Standardize on spaces for indentations
* Update `` to $()

Author: unixorn

bin/git-prune-branches

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # git-prune-branches
 #
@@ -14,40 +14,42 @@
 # License: MIT
 # Original source: https://github.com/jut-io/git-scripts/blob/master/bin/git-prune-branches
 
-merged=`git branch --no-color --merged master | grep -v master | sed 's/\*/ /'`
+merged=$(git branch --no-color --merged master | grep -v master | sed 's/\*/ /')
 
 if [ ! -z "$merged" ] ; then
     echo "Deleting the following merged branches:"
     for branch in $merged ; do
-	echo "    " $branch
+        echo "    " "$branch"
     done
 
     all=n
     delete=n
     for branch in $merged ; do
-	if [ $all = 'n' ] ; then
-            delete=n
-            read -p "Delete $branch (y=yes, n=no, a=all)? " prompt
-	    echo "all=$all delete=$delete prompt=$prompt"
-            if [ "$prompt" = 'a' ] ; then
-		delete=y
-		all=y
-	    elif [ "$prompt" = 'y' ]; then
-		delete=y
-	    fi
-	fi
+    if [ $all = 'n' ] ; then
+        delete=n
+        # shellcheck disable=SC2162
+        read -p "Delete $branch (y=yes, n=no, a=all)? " prompt
+        echo "all=$all delete=$delete prompt=$prompt"
+        if [ "$prompt" = 'a' ] ; then
+            delete=y
+            all=y
+        elif [ "$prompt" = 'y' ]; then
+            delete=y
+        fi
+    fi
 
-	if [ "$delete" = 'y' ] ; then
-	    git branch -d $branch
-	fi
+    if [ "$delete" = 'y' ] ; then
+        git branch -d "$branch"
+    fi
     done
 fi
 
-remotes=`git remote`
+remotes=$(git remote)
 for remote in $remotes ; do
     prompt=n
+    # shellcheck disable=SC2162
     read -p "Prune deleted branches from remote '$remote' (y=yes n=no)? " prompt
     if [ "$prompt" = 'y' ] ; then
-	git remote prune $remote
+        git remote prune "$remote"
     fi
 done