bash的检查，如果文件夹有内容
问题说明
我试图创建一个bash脚本，将删除我的 .waste 目录中的一切。我有我写了一个基本的脚本，但我想它首先检查 .waste 目录中有内容，如果有的话，呼应出一个简单的 文件夹已空的！消息。我不是太精明关于如果和如果别人声明，我不知道是什么 [] 公式我需要把检查presence。
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 [ ] equation I'd need to put in to check for presence.
基本code：
#! /bin/bash
echo "The files have been deleted:"
cd /home/user/bin/.waste/
ls
rm -rf /home/user/bin/.waste/*
任何帮助将是AP preciated！
Any help would be appreciated!
（PS不知道星号是在最后正确的，我也尝试用它的脚本，我记得它删除了斌目录中的一切以及）
(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)
正确答案
您可以检查一个目录是空的是这样的：
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
或者更好的是：
#!/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
如果该目录包含多个文件，这可以是慢。在这种情况下，这应该是较快
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 $target is empty '(or non-existent)'
fi
的找到命令将打印并退出发现里面的第一个文件或目录$目标之后。在的grep -q。将成功退出只有当找到打印任何东西，换句话说，如果有任何文件。
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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