Shellchecker corrections

* https://github.com/koalaman/shellcheck/wiki/SC2164
* https://github.com/koalaman/shellcheck/wiki/SC2046
* https://github.com/koalaman/shellcheck/wiki/SC2006
* trim spacing

Author: camlafit

inst/bin/switch-phpfarm

@@ -1,9 +1,9 @@
 #!/bin/sh
-basedir="`dirname "$0"`/../"
-cd "$basedir"
-basedir=`pwd`
+basedir="$(dirname "$0")/../"
+cd "$basedir" || exit
+basedir="$(pwd)"
 binlink="$basedir/current"
-active=`basename $(readlink "$binlink") 2>/dev/null | sed -e 's/^php-//;s/\./\\\\./g'`
+active=`basename "$(readlink "$binlink")" 2>/dev/null | sed -e 's/^php-//;s/\./\\\\./g'`
 
 php_system=""
 if [ -f "/usr/bin/php" ]; then
@@ -23,17 +23,17 @@ fi
 version="$1"
 phpdir="php-$version"
 
-if [ $version != "$php_system" ]; then
+if [ "$version" != "$php_system" ]; then
     if [ ! -d "$basedir/$phpdir" ]; then
        echo "PHP version $version is not installed"
        exit 2
     else
-       echo Setting active PHP version to $version
+       echo "Setting active PHP version to $version"
        ln -sfT "$phpdir" "$binlink"
-       $basedir/current/bin/php --version
+       "$basedir/current/bin/php" --version
     fi
-else 
+else
    echo "Setting active PHP version to system version ($version)"
    rm -f "$binlink"
    php --version
-fi 
+fi