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translating---geekpi
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3 Ways to Permanently and Securely Delete ‘Files and Directories’ in Linux
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============================================================
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In most cases the means we use to [delete a file from our computers][1] such as using `Delete` key, Trash files or `rm` command, which do not permanently and securely remove the file from the hard disk (or any storage media).
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The file is simply hidden from users and it resides somewhere on the hard disk. It can be recovered by data thieves, law enforcement or other threats.
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Assuming a file contains classified or secret content such as usernames and passwords of a security system, an attacker with the necessary knowledge and skills can easily [recover a deleted copy of the file][2] and access these user credentials (and you can probably guess the aftermath of such as scenario).
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In this article, we will explain a number of command line tools for permanently and securely deleting files in Linux.
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### 1\. Shred – Overwrite a File to Hide Content
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shred overwrites a file to hide its contents, and can optionally delete it as well.
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```
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$ shred -zvu -n 5 passwords.list
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```
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In the command below, the options:
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1. `-z` – adds a final overwrite with zeros to hide shredding
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2. `-v` – enables display of operation progress
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3. `-u` – truncates and removes file after overwriting
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4. `-n` – specifies number of times to overwrite file content (the default is 3)
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[
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][3]
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shred – overwrite a file to hide its contents
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You can find more usage options and information in the shred man page:
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```
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$ man shred
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```
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### 2\. Wipe – Securely Erase Files in Linux
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A Linux wipe command securely erases files from magnetic memory and thereby making it impossible to [recover deleted files or directory content][4].
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First, you need to install wipe tool in order to it, run the appropriate command below:
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```
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$ sudo apt-get install wipe [On Debian and its derivatives]
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$ sudo yum install wipe [On RedHat based systems]
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```
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The following command will destroy everything under the directory private.
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```
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$ wipe -rfi private/*
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```
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where the flags used:
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1. `-r` – tells wipe to recurse into subdirectories
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2. `-f` – enables forced deletion and disable confirmation query
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3. `-i` – shows progress of deletion process
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[
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][5]
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Wipe – Securely Erase Files in Linux
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Note: Wipe only works reliably on magnetic memory, therefore use the other methods for solid state disks (memory).
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Read through the wipe man page for additional usage options and instructions:
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```
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$ man wipe
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```
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### 3\. Secure-deletetion Toolkit for Linux
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Secure-delete is a collection of secure file deletion tools, that contains srm (secure_deletion) tool, which is used to remove files securely.
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First you need to install it using the relevant command below:
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```
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$ sudo apt-get install secure-delete [On Debian and its derivatives]
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$ sudo yum install secure-delete [On RedHat based systems]
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```
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Once installed, you can use srm tool to remove files or directories securely on a Linux system as follows.
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```
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$ srm -vz private/*
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```
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where the options used:
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1. `-v` – enables verbose mode
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2. `-z` – wipes the last write with zeros instead of random data
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[
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][6]
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srm – Securely Delete Files in Linux
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Read through the srm man page for more usage options and information:
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```
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$ man srm
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```
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### 4\. sfill -Secure Free Disk/Inode Space Wiper
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sfill is a part of secure-deletetion toolkit, is a secure free disk and inode space wiper, it deletes files on free disk space in a secure method. sfill [checks the the free space on the specified partition][7] and fills it with random data from /dev/urandom.
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The command below will execute sfill on my root partition, with the `-v` switch enabling verbose mode:
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```
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$ sudo sfill -v /home/aaronkilik/tmp/
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```
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Assuming you created a separate partition, `/home` to store normal system users home directories, you can specify a directory on that partition to apply sfill on it:
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```
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$ sudo sfill -v /home/username
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```
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The are a few limitations of sfill that you can read about in the man page, where you can also find additional usage flags and instructions:
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```
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$ man sfill
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```
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Note: These following two tools (sswap and sdmem) in the secure-deletetion toolkit are not directly relevant for the scope of this guide, however, we will explain them for knowledge purpose and future use.
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### 5\. sswap – Secure Swap Wiper
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It is a secure partition wiper, sswap deletes data present on your swap partition in a secure manner.
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Caution: remember to unmount your swap partition before using sswap! Otherwise your system might crash!
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Simply determine you swap partition (and check if paging and swapping devices/files are turned on using swapon command), next, disable paging and swapping devices/files with swapoff command (renders swap partition unusable).
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Then run sswap command on the swap partition:
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```
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$ cat /proc/swaps
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$ swapon
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$ sudo swapoff /dev/sda6
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$ sudo sswap /dev/sda6 #this command may take some time to complete with 38 default passes
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```
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[
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][8]
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sswap – Secure Swap Wiper
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Make an effort to read through the sswap man page for more usage options and information:
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```
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$ man sswap
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```
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### 6\. sdmem – Secure Memory Wiper
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sdmem is a secure memory wiper, it is designed to remove data present in your memory (RAM) in a secure manner.
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It was originally named [smem][9], but because on Debain systems there exists another package called [smem – report memory consumption on per-process and per-user basis][10], the developer decided to rename it sdmem.
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```
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$ sudo sdmem -f -v
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```
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For more usage information, read through the sdmem man page:
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```
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$ man sdmem
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```
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**Suggested Read:** [PhotoRec – Recover Deleted or Lost Files in Linux][11]
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That’s it! In this article, we reviewed a number command line tools for permanently as well as securely deleting files in Linux. As usual, offer your thoughts or suggestions about the post via the comment form below.
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--------------------------------------------------------------------------------
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作者简介：
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||||
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||||
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I am Ravi Saive, creator of TecMint. A Computer Geek and Linux Guru who loves to share tricks and tips on Internet. Most Of My Servers runs on Open Source Platform called Linux. Follow Me: Twitter, Facebook and Google+
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--------------------------------------------------------------------------------
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via: http://www.tecmint.com/permanently-and-securely-delete-files-directories-linux/
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作者：[Ravi Saive][a]
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译者：[译者ID](https://github.com/译者ID)
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||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/admin/
|
||||
[1]:http://www.tecmint.com/delete-all-files-in-directory-except-one-few-file-extensions/
|
||||
[2]:http://www.tecmint.com/photorec-recover-deleted-lost-files-in-linux/
|
||||
[3]:http://www.tecmint.com/wp-content/uploads/2017/01/shred-command-example.png
|
||||
[4]:http://www.tecmint.com/recover-deleted-file-in-linux/
|
||||
[5]:http://www.tecmint.com/wp-content/uploads/2017/01/Wipe-Securely-Erase-Files.png
|
||||
[6]:http://www.tecmint.com/wp-content/uploads/2017/01/srm-securely-delete-Files-in-Linux.png
|
||||
[7]:http://www.tecmint.com/find-top-large-directories-and-files-sizes-in-linux/
|
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[8]:http://www.tecmint.com/wp-content/uploads/2017/01/sswap-Secure-Swap-Wiper.png
|
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[9]:http://www.tecmint.com/smem-linux-memory-usage-per-process-per-user/
|
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[10]:http://www.tecmint.com/smem-linux-memory-usage-per-process-per-user/
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[11]:http://www.tecmint.com/photorec-recover-deleted-lost-files-in-linux/
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@ -0,0 +1,210 @@
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3 个在 Linux 中永久并安全删除`文件和目录`的方法
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============================================================
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在大多数情况下，我们习惯于[从我们的计算机中删除文件][1]，例如使用 `Delete` 键、垃圾箱或 `rm` 命令，这不是永久安全地从硬盘中（或任何存储介质）删除文件的方法。
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该文件只是对用户隐藏，它驻留在硬盘上的某个地方。它可以通过数据窃贼、执法或其他威胁来恢复。
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假设文件包含密级或机密内容，例如安全系统的用户名和密码，具有必要知识和技能的攻击者可以轻松地[恢复删除文件的副本][2]并访问这些用户凭证（你可以猜测到这种情况的后果）。
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在本文中，我们将解释一些命令行工具，用于永久并安全地删除 Linux 中的文件。
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### 1\. shred – 覆盖文件来隐藏内容
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shred 会覆盖文件来隐藏它的内容，并且也可以选择删除它。
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```
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$ shred -zvu -n 5 passwords.list
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```
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在下面的命令中，选项有：
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1. `-z` - 用零覆盖以隐藏碎片
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2. `-v` - 显示操作进度
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3. `-u` - 在覆盖后截断并删除文件
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4. `-n` - 指定覆盖文件内容的次数（默认值为3）
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[
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][3]
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shred - 覆盖文件来隐藏它的内容
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你可以在 shred 的帮助页中找到更多的用法选项和信息：
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```
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$ man shred
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```
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### 2\. wipe – 在 Linux 中安全删除文件
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Linux wipe 命令可以安全地擦除磁盘中的文件，从而不可能[恢复删除的文件或目录内容] 4]。
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首先，你需要安装 wipe 工具，运行以下适当的命令：
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```
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$ sudo apt-get install wipe [On Debian and its derivatives]
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$ sudo yum install wipe [On RedHat based systems]
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```
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下面的命令会摧毁 private 目录下的所有文件。
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```
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$ wipe -rfi private/*
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```
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当使用下面的标志时：
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1. `-r` - 告诉 wipe 递归擦除子目录
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2. `-f` - 启用强制删除并禁用确认查询
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3. `-i` - 显示擦除进度
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[
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][5]
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wipe – 在 Linux 中安全擦除文件
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注意：wipe 仅在磁性存储上可以可靠地工作，因此对固态磁盘（内存）请使用其他方法。
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阅读 wipe 手册以获取其他使用选项和说明：
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```
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$ man wipe
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```
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### 3\. Linux 中的安全删除工具集
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secure-delete 是一个安全文件删除工具的集合，它包含srm（secure_deletion）工具，用于安全删除文件。
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首先，你需要使用以下相关命令安装它：
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```
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$ sudo apt-get install secure-delete [On Debian and its derivatives]
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$ sudo yum install secure-delete [On RedHat based systems]
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```
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安装完成后，你可以使用 srm 工具在 Linux 中安全地删除文件和目录。
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```
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$ srm -vz private/*
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```
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下面是使用的选项：
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1. `-v` – 启用 verbose 模式
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2. `-z` – 用0而不是随机数据来擦除最后的写入
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[
|
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|
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][6]
|
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srm – 在 Linux 中安全删除文件
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|
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阅读 srm 手册来获取更多的使用选项和信息：
|
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|
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```
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$ man srm
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```
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### 4\. sfill -安全免费的磁盘/inode 空间擦除器
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sfill 是 secure-deletetion 工具包的一部分，是一个安全免费的磁盘和 inode 空间擦除器，它以安全的方法删除可用磁盘空间中的文件。 sfill 会[检查指定分区上的可用空间][7]，并使用来自 /dev/urandom 的随机数据填充它。
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以下命令将在我的根分区上执行 sfill，使用 `-v' 选项启用 verbose 模式：
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```
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$ sudo sfill -v /home/aaronkilik/tmp/
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```
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假设你创建了一个单独的分区 `/home` 来存储正常的系统用户主目录，你可以在该分区上指定一个目录，以便在其上应用 sfill：
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```
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$ sudo sfill -v /home/username
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```
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你可以在 sfill 的手册上看到一些限制，你也可以看到额外的使用标志和命令：
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```
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$ man sfill
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```
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注意：secure-deletetion 工具包中的两个工具（sswap 和 sdmem）与本指南的范围不直接相关，但是，我们会在将来为了传播知识的目的来解释它们。
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### 5\. sswap – 安全 swap 擦除器
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它是一个安全的分区擦除器，sswap以安全的方式删除 swap 分区上存在的数据。
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警告：请记住在使用 sswap 之前卸载 swap 分区！ 否则你的系统可能会崩溃！
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只需确定交换分区（并检查分页和交换设备/文件是否使用 swapon 命令打开），接下来，使用 swapoff 命令禁用分页和交换设备/文件（使 swap 分区不可用）。
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然后在 swap 分区上运行 sswap 命令：
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```
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$ cat /proc/swaps
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$ swapon
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$ sudo swapoff /dev/sda6
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$ sudo sswap /dev/sda6 #this command may take some time to complete with 38 default passes
|
||||
```
|
||||
[
|
||||
|
||||
][8]
|
||||
|
||||
sswap – 安全 swap 擦除器
|
||||
|
||||
阅读 sswap 的手册来获取更多的选项和信息：
|
||||
|
||||
```
|
||||
$ man sswap
|
||||
```
|
||||
|
||||
### 6\. sdmem – 安全内存擦除器
|
||||
|
||||
sdmem 是一个安全的内存擦除器，它被设计为以安全的方式删除存储器（RAM）中的数据。
|
||||
|
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它最初命名为[smem][9]，但是因为在 Debain 系统上存在另一个包[smem - 报告每个进程和每个用户的内存消耗][10]，开发人员决定将它重命名为 sdmem。
|
||||
|
||||
```
|
||||
$ sudo sdmem -f -v
|
||||
```
|
||||
|
||||
关于更多的使用信息，阅读 sdmen 的手册：
|
||||
|
||||
```
|
||||
$ man sdmem
|
||||
```
|
||||
|
||||
**推荐阅读：** [PhotoRec – 在 Linux 中恢复删除或遗失的文件][11]
|
||||
|
||||
就是这样了！在本文中，我们审查了一系列可以永久安全地删除 Linux 中的文件的工具。像往常一样，通过下面的评论栏发表你对本篇文章的想法或建议。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
作者简介：
|
||||
|
||||
|
||||
我是 Ravi Saive，TecMint 的创建者。 一个计算机 Geek 和 Linux 大师，喜欢在互联网上分享技巧和贴士。我的服务器大多数运行在称为 Linux 的开源平台上。关注我：Twitter、Facebook 和 Google+
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/permanently-and-securely-delete-files-directories-linux/
|
||||
|
||||
作者：[Ravi Saive][a]
|
||||
译者：[geekpi](https://github.com/geekpi)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/admin/
|
||||
[1]:http://www.tecmint.com/delete-all-files-in-directory-except-one-few-file-extensions/
|
||||
[2]:http://www.tecmint.com/photorec-recover-deleted-lost-files-in-linux/
|
||||
[3]:http://www.tecmint.com/wp-content/uploads/2017/01/shred-command-example.png
|
||||
[4]:http://www.tecmint.com/recover-deleted-file-in-linux/
|
||||
[5]:http://www.tecmint.com/wp-content/uploads/2017/01/Wipe-Securely-Erase-Files.png
|
||||
[6]:http://www.tecmint.com/wp-content/uploads/2017/01/srm-securely-delete-Files-in-Linux.png
|
||||
[7]:http://www.tecmint.com/find-top-large-directories-and-files-sizes-in-linux/
|
||||
[8]:http://www.tecmint.com/wp-content/uploads/2017/01/sswap-Secure-Swap-Wiper.png
|
||||
[9]:http://www.tecmint.com/smem-linux-memory-usage-per-process-per-user/
|
||||
[10]:http://www.tecmint.com/smem-linux-memory-usage-per-process-per-user/
|
||||
[11]:http://www.tecmint.com/photorec-recover-deleted-lost-files-in-linux/
|
||||
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