Bash中判斷一個命令的輸出結果是否為空

如果我們想在Bash中判斷一個命令的輸出結果是否為空，我們可以使用test命令和-z參數。示例代碼如下：

if test -z "$(ls | grep test1.txt)"; then
    echo "The result is empty."
else
    echo "The result is not empty."
fi
 
if test ! -z "$(ls | grep test2.txt)"; then
    echo "The result is not empty."
else
    echo "The result is empty."
fi