linux不像windows有個回收站，使用rm -rf *基本上文件是找不回來的。
那么問題來了：
對於linux下誤刪的文件，我們是否真的無法通過軟件進行恢復呢?
答案當然是否定的，對於誤刪的文件，我們還是能通過軟件恢復過來的。對於誤刪文件還原可以分為兩種情況:
一種是刪除以后在進程存在刪除信息
一種是刪除以后進程都找不到，只有借助於工具還原。
接下來以例子分別解說下兩種不同的誤刪還原方式：
誤刪除文件進程還在的情況:
這種一般是有活動的進程存在持續標准輸入或輸出，到時文件被刪除后，進程PID依舊存在。這也是有些服務器刪除一些文件但是磁盤不釋放的原因。
打開一個終端對一個測試文件做cat追加操作：
[root@docking ~]# echo "This is DeleteFile test." > deletefile.txt
[root@docking ~]# ls
deletefile.txt
[root@docking ~]# cat >> deletefile.txt
Add SomeLine into deletefile for fun.
打開另外一個終端查看這個文件可以清楚看到內容：
[root@docking ~]# ls
deletefile.txt
[root@docking ~]# cat deletefile.txt
This is DeleteFile test.
Add SomeLine into deletefile for fun.
此時，刪除文件rm -f deletefile.txt
[root@docking ~]# rm -f deletefile.txt
[root@docking ~]# ls
命令查看這個目錄，文件已經不存在了，那么現在我們將其恢復出來。
lsof查看刪除的文件進程是否還存在。
如沒有安裝請自行yum install lsof或者apt-get install lsof
1.類似這種情況，我們可以先lsof查看刪除的文件 是否還在
[root@docking ~]# lsof | grep deletefile
cat 21796 root 1w REG 253,1 63 138860 /root/deletefile.txt (deleted)
2.恢復cp /proc/pid/fd/1 /指定目錄/文件名
進入 進程目錄，一般是進入/proc/pid/fd/,針對當前情況：
[root@docking ~]# cd /proc/21796/fd
[root@docking fd]# ll
總用量 0
lrwx------ 1 root root 64 1月 18 22:21 0 -> /dev/pts/0
l-wx------ 1 root root 64 1月 18 22:21 1 -> /root/deletefile.txt (deleted)
lrwx------ 1 root root 64 1月 18 22:21 2 -> /dev/pts/0
恢復操作：
[root@docking fd]# cp 1 ~/deletefile.txt.backup
[root@docking fd]# cat ~/deletefile.txt.backup
This is DeleteFile test.
Add SomeLine into deletefile for fun.
3.恢復完成。
誤刪除的文件進程已經不存在，借助於工具還原
准備一些文件目錄
准備一份掛載的盤
mkdir backuptest
cd backuptest
mkdir deletetest
mkdir deletetest/innerfolder
echo "Delete a folder test." > deletetest/innerfolder/deletefile.txt
echo "tcpdump:x:172:72::/:/sbin/nologin" > tmppasswd
最后准備的目錄結構如下：
taroballs@taroballs-PC:/media/taroballs/taroballs/backuptest$ cd ..
taroballs@taroballs-PC:/media/taroballs/taroballs$ tree backuptest/
backuptest/
├── deletetest
│ └── innerfolder
│ └── deletefile.txt
└── tmppasswd
2 directories, 2 files
現在開始刪除該目錄rm -rf backuptest/
taroballs@taroballs-PC:/media/taroballs/taroballs$ rm -rf backuptest/
taroballs@taroballs-PC:/media/taroballs/taroballs$ ls -l
總用量 0
這種情況一般是沒有守護進行或者后台進程對其持續輸入，所以刪除就真的刪除了。lsof也看不到，故需要采用工具進行恢復。
現在開始進行誤刪除文件的恢復。
我們采用的工具是extundelete第三方工具。恢復步驟以及注意事項如下：
停止對當前分區做任何操作，防止inode被覆蓋。inode被覆蓋基本就告別恢復了。
誇張一點講，比如停止所在分區的服務，卸載目錄所在的設備，有必要的情況下都可以斷網。
通過dd命令對 當前分區進行備份，防止第三方軟件恢復失敗導致數據丟失。
適合數據非常重要的情況，這里是例子，所以就沒有備份，如備份可以考慮如下方式：dd if=/path/filename of=/dev/vdc1
通過umount命令，對當前設備分區卸載。或者fuser 命令umount /dev/vdb1
如果提示設備busy，可以用fuser命令強制卸載：fuser -m -v -i -k ./
下載第三方工具extundelete安裝，搜索誤刪除的文件進行還原
extundelete工具安裝
extundelete下載地址：http://extundelete.sourceforge.net/
wget https://nchc.dl.sourceforge.net/project/extundelete/extundelete/0.2.4/extundelete-0.2.4.tar.bz2
解壓該文件tar jxvf extundelete-0.2.4.tar.bz2
若報這種錯誤
[root@docking ~]# tar jxvf extundelete-0.2.4.tar.bz2
tar (child): bzip2：無法 exec: 沒有那個文件或目錄
tar (child): Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error is not recoverable: exiting now
則使用yum -y install bzip2進行解決
[root@docking ~]# tar jxvf extundelete-0.2.4.tar.bz2
extundelete-0.2.4/
extundelete-0.2.4/acinclude.m4
extundelete-0.2.4/missing
extundelete-0.2.4/autogen.sh
extundelete-0.2.4/aclocal.m4
extundelete-0.2.4/configure
extundelete-0.2.4/LICENSE
extundelete-0.2.4/README
...................................................
cd extundelete-0.2.4
./configure
若這步驟報錯
[root@docking extundelete-0.2.4]# ./configure
Configuring extundelete 0.2.4
configure: error: in `/root/extundelete-0.2.4':
configure: error: C++ compiler cannot create executables
See `config.log' for more details
則使用yum -y install gcc-c++解決.
若執行上一步仍然報錯，
[root@docking extundelete-0.2.4]# ./configure
Configuring extundelete 0.2.4
configure: error: Can't find ext2fs library
則使用yum -y install e2fsprogs e2fsprogs-devel來解決。
#Ubuntu的解決辦法為sudo apt-get install e2fslibs-dev e2fslibs-dev
不出意外的話到這里應該configure能夠順利完成.
[root@docking extundelete-0.2.4]# ./configure
Configuring extundelete 0.2.4
Writing generated files to disk
[root@docking extundelete-0.2.4]#
最后make然后 make install
[root@docking extundelete-0.2.4]# make
make -s all-recursive
Making all in src
extundelete.cc: 在函數‘ext2_ino_t find_inode(ext2_filsys, ext2_filsys, ext2_inode*, std::string, int)’中:
extundelete.cc:1272:29: 警告：在 {} 內將‘search_flags’從‘int’轉換為較窄的類型‘ext2_ino_t {aka unsigned int}’ [-Wnarrowing]
buf, match_name2, priv, 0};
^
[root@docking extundelete-0.2.4]# make install
Making install in src
/usr/bin/install -c extundelete '/usr/local/bin'
extundelete安裝完成.
掃描誤刪除的文件：
使用df -lh查看掛載：
taroballs@taroballs-PC:~$ df -lh
文件系統 容量 已用 可用 已用% 掛載點
udev 1.9G 0 1.9G 0% /dev
tmpfs 387M 1.8M 385M 1% /run
/dev/sda2 92G 61G 26G 71% /
tmpfs 1.9G 49M 1.9G 3% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda3 104G 56G 44G 57% /home
tmpfs 387M 40K 387M 1% /run/user/1000
/dev/sda4 70G 20G 47G 30% /media/taroballs/d8423f8c-d687-4c03-a7c8-06a7fb57f96d
/dev/sdb1 6.8G 4.1G 2.8G 60% /media/taroballs/taroballs
/dev/sr0 4.0G 4.0G 0 100% /media/taroballs/2018-01-16-12-36-00-00
taroballs@taroballs-PC:~$ cd /media/taroballs/taroballs/
taroballs@taroballs-PC:/media/taroballs/taroballs$
可以看到，我們的目錄/media/taroballs/taroballs
掛載到/dev/sdb1 這個文件系統中.
umount我們的掛載盤
比如：
taroballs@taroballs-PC:~$ df -lh | grep /dev/sdb1
/dev/sdb1 6.8G 4.1G 2.8G 60% /media/taroballs/taroballs
umount這個目錄
taroballs@taroballs-PC:~$ umount /media/taroballs/taroballs
taroballs@taroballs-PC:~$ df -lh | grep /dev/sdb1
taroballs@taroballs-PC:~$
記得刪除一定要后umount哦，不然二次寫入誰也幫不了你呢。
通過inode節點恢復
taroballs@taroballs-PC:~$ mkdir recovertest
taroballs@taroballs-PC:~$ cd recovertest/
taroballs@taroballs-PC:~/recovertest$
執行恢復extundelete /dev/sdb1 --inode 2
taroballs@taroballs-PC:/media/taroballs/taroballs$ sudo extundelete /dev/sdb1 --inode 2
NOTICE: Extended attributes are not restored.
Loading filesystem metadata ... 8 groups loaded.
Group: 0
Contents of inode 2:
.
.省略N行
File name | Inode number | Deleted status
. 2
.. 2
deletetest 12 Deleted
tmppasswd 14 Deleted
通過掃描發現了我們刪除的文件夾，現在執行恢復操作。
（1）恢復單一文件tmppasswd
taroballs@taroballs-PC:~/recovertest$ extundelete /dev/sdb1 --restore-file passwd
NOTICE: Extended attributes are not restored.
Loading filesystem metadata ... 8 groups loaded.
Loading journal descriptors ... 46 descriptors loaded.
Successfully restored file tmppasswd
恢復文件是放到了當前目錄RECOVERED_FILES。
查看恢復的文件：
taroballs@taroballs-PC:~/recovertest$ cat tmppasswd
tcpdump:x:172:72::/:/sbin/nologin
（2）恢復目錄deletetest
extundelete /dev/sdb1 --restore-directory deletetest
NOTICE: Extended attributes are not restored.
Loading filesystem metadata ... 8 groups loaded.
Loading journal descriptors ... 46 descriptors loaded.
Searching for recoverable inodes in directory deletetest ...
5 recoverable inodes found.
Looking through the directory structure for deleted files ...
（3）恢復所有
taroballs@taroballs-PC:~/recovertest$ extundelete /dev/sdb1 --restore-all
NOTICE: Extended attributes are not restored.
Loading filesystem metadata ... 8 groups loaded.
Loading journal descriptors ... 46 descriptors loaded.
Searching for recoverable inodes in directory / ...
5 recoverable inodes found.
Looking through the directory structure for deleted files ...
0 recoverable inodes still lost.
taroballs@taroballs-PC:~/recovertest$ tree
backuptest/
├── deletetest
│ └── innerfolder
│ └── deletefile.txt
└── tmppasswd
2 directories, 2 files
（4）恢復指定inode
taroballs@taroballs-PC:~/recovertest$ extundelete /dev/sdb1 --restore-inode 14
NOTICE: Extended attributes are not restored.
Loading filesystem metadata ... 8 groups loaded.
Loading journal descriptors ... 46 descriptors loaded.
taroballs@taroballs-PC:~/recovertest$ cat file.14
tcpdump:x:172:72::/:/sbin/nologin
注意恢復inode的時候，恢復 出來的文件名和之前不一樣，需要單獨進行改名。
最后附上extundelete的用法:
$ extundelete --help
Usage: extundelete [options] [--] device-file
Options:
--version, -[vV] Print version and exit successfully.
--help, Print this help and exit successfully.
--superblock Print contents of superblock in addition to the rest.
If no action is specified then this option is implied.
--journal Show content of journal.
--after dtime Only process entries deleted on or after 'dtime'.
--before dtime Only process entries deleted before 'dtime'.
Actions:
--inode ino Show info on inode 'ino'.
--block blk Show info on block 'blk'.
--restore-inode ino[,ino,...]
Restore the file(s) with known inode number 'ino'.
The restored files are created in ./RECOVERED_FILES
with their inode number as extension (ie, file.12345).
--restore-file 'path' Will restore file 'path'. 'path' is relative to root
of the partition and does not start with a '/'
The restored file is created in the current
directory as 'RECOVERED_FILES/path'.
--restore-files 'path' Will restore files which are listed in the file 'path'.
Each filename should be in the same format as an option
to --restore-file, and there should be one per line.
--restore-directory 'path'
Will restore directory 'path'. 'path' is relative to the
root directory of the file system. The restored
directory is created in the output directory as 'path'.
--restore-all Attempts to restore everything.
-j journal Reads an external journal from the named file.
-b blocknumber Uses the backup superblock at blocknumber when opening
the file system.
-B blocksize Uses blocksize as the block size when opening the file
system. The number should be the number of bytes.
--log 0 Make the program silent.
--log filename Logs all messages to filename.
--log D1=0,D2=filename Custom control of log messages with comma-separated
Examples below: list of options. Dn must be one of info, warn, or
--log info,error error. Omission of the '=name' results in messages
--log warn=0 with the specified level to be logged to the console.
--log error=filename If the parameter is '=0', logging for the specified
level will be turned off. If the parameter is
'=filename', messages with that level will be written
to filename.
-o directory Save the recovered files to the named directory.
The restored files are created in a directory
named 'RECOVERED_FILES/' by default.