when exa is not installed, don't prevent use of ls

shell_common/.config/shell_common/aliases.sh

@@ -31,9 +31,13 @@ ffe() {
 	${EDITOR:-nvim} "$fname"
 }
 
-alias ls='exa' # -ag
-alias la='exa -l'
-alias ll='exa -lahg'
+if [ -x "$(command -v "exa")" ]; then
+	alias ls='exa' # -ag
+	alias la='exa -l'
+	alias ll='exa -lahg'
+else
+	echo "exa not installed"
+fi
 
 alias pu='git push'
 alias st='git st'