Bash检查文件夹是否有内容 [英] Bash checking if folder has contents

问题描述

我正在尝试创建一个Bash脚本，它将删除我的 .waste 目录中的所有内容。我有一个我写的基本脚本，但是我想要首先检查 .waste 目录是否具有内容，如果是，回显一个简单的 文件夹已经空了！消息。对于如果和 if else 语句，我不太清楚，我不知道 [] 方程需要检查存在。

I'm trying to create a Bash script that will delete everything in my .waste directory. I have a basic script I wrote but I want it to first check if the .waste directory has contents, and if so, to echo out a simple "Folder already empty!" message. I'm not too savvy about if and if else statements, and I don't know what the [ ] equation needs to check for presence.

基本代码

#! /bin/bash
echo "The files have been deleted:"
cd /home/user/bin/.waste/
ls
rm -rf /home/user/bin/.waste/*

（PS不知道星号在最后是否正确，该脚本与它，我记得它删除了 bin 目录中的所有内容）

(P.S. not sure if the asterisk is correct at the end, I did try the script with it and I recall it deleted everything in the bin directory as well)

推荐答案

您可以检查目录是否为空，如下所示：

You can check if a directory is empty like this:

#!/bin/sh
target=$1
test "$(ls -A "$target" 2>/dev/null)" || echo The directory $target is empty

还是更好：

#!/bin/sh
target=$1
if test "$(ls -A "$target")"; then
    echo not empty, do something
else
    echo The directory $target is empty '(or non-existent)'
fi

更新

如果目录包含很多文件，这可能很慢。在这种情况下，这应该更快：

UPDATE

If the directory contains many files, this can be slow. In that case, this should be faster:

#!/bin/sh
target=$1
if find "$target" -mindepth 1 -print -quit | grep -q .; then
    echo not empty, do something
else
    echo The directory $target is empty '(or non-existent)'
fi

find 命令将打印并退出后，找到第一个文件或目录 $目标。 grep -q。只有在找到打印任何东西时才会退出，换句话说，如果有文件。

The find command will print and quit after it finds the first file or directory inside $target. The grep -q . will exit with success only if the find printed anything, in other words, if there were any files.

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