shell-scripts: Use [[ instead of [ where possible

Replace all occurrences of [ with [[ in bash and zsh scripts and
configs.
Performance wise it makes sense to use the builtin instead of calling an
external command also when from a functionality stand point `test` would
suffice.

.config/zsh/autoload/clang-format

@@ -12,7 +12,7 @@ if (( ! idx )); then
 fi
 
 local style="${@[$idx]#-style}" prefix=""
-if [ -n "$style" ]; then
+if [[ -n "$style" ]]; then
 	# Flag was given in form -style=<style>
 	style="${style#=}"
 	prefix="-style="
@@ -21,7 +21,7 @@ else
 	(( idx++ ))
 	style="${@[$idx]}"
 fi
-if [ ! -e "$style" ]; then
+if [[ ! -e "$style" ]]; then
 	# Argument is not a file and thus probably a valid style string that can
 	# be passes to clang-format
 	command clang-format "$@"

.config/zsh/autoload/git-submodule-rm

@@ -7,7 +7,7 @@
 local toplevel="$(git rev-parse --show-toplevel)" || return
 
 # Exit if no arguements were given
-[ $# -gt 0 ] || return
+[[ $# -gt 0 ]] || return
 
 local separator=""
 for arg in "$@"; do
@@ -16,11 +16,11 @@ for arg in "$@"; do
 	# argument relative from git toplevel
 	local arg_from_git="${${arg:A}##$toplevel/}"
 	# argument has to exist
-	[ -e "$arg" ] || continue
+	[[ -e "$arg" ]] || continue
 	# argument has to exist in repo
-	[ -e "$toplevel/$arg_from_git" ] || continue
+	[[ -e "$toplevel/$arg_from_git" ]] || continue
 	# has to be a submodule
-	[ -e "$toplevel/.git/modules/$arg_from_git" ] || continue
+	[[ -e "$toplevel/.git/modules/$arg_from_git" ]] || continue
 
 	git submodule deinit -f  "$arg"
 	echo "command rm -rf \"$toplevel/.git/modules/$arg_from_git\""

.config/zsh/autoload/glog

@@ -52,7 +52,7 @@ local -a fzf_args=(
 	# Execute git show on the commit as preview.
 	"--preview" "
 		out=\"\$(echo {} | sed -Ee \"$del_ansi\" -e \"$commit_hash\")\"
-		if [ \"\$out\" ]; then
+		if [[ \"\$out\" ]]; then
 			git show \"${(j:%n:)format}\" \"$date\" $colors \"\$out\" \
 			| diff-so-fancy
 		fi

.config/zsh/autoload/ls

@@ -20,9 +20,9 @@ builtin local -a dirs files
 # All other arguments are kept.
 for arg in "$@"; do
 	shift
-	if [ -d "$arg" ]; then
+	if [[ -d "$arg" ]]; then
 		dirs+="$arg"
-	elif [ -e "$arg" ]; then
+	elif [[ -e "$arg" ]]; then
 		files+="$arg"
 	else
 		set -- "$@" "$arg"
@@ -36,7 +36,7 @@ fi
 
 # Do not separate files and directories if -d flag was specified.
 while getopts d flag 2>/dev/null; do
-	if [ "$flag" = "d" ]; then
+	if [[ "$flag" = "d" ]]; then
 		command ls "$@" -- "${files[@]}" "${dirs[@]}"
 		return
 	fi