CODEWITHSUNDEEP
bashfilesystemsinode
user619271
user619271

Reputation: 5002

How to get file contents by inode in Bash?

How can I retrieve file contents in Bash by knowing only the inode of the file?

Upvotes: 22

Views: 19008

Answers (4)

Derlin
Derlin

Reputation: 9891

As per this unixexchange answer:

You cannot access files by inodes, because that would break access control via permissions. For example, if you don't have the permission to traverse a directory, then you can't access any of the files in that directory no matter what the permissions on the file are. If you could access a file by inode, that would bypass directory permissions.

There is some ways to get the path or name of a file through an inode number though, for example using find. Once you get one path to the file, you can use any of the regular tools.

find has an inum argument to look up files by inodes. Here is an example:

find -inum 1704744 -exec cat {} \;

This will print the content of the file with inode 1704744, assuming it is located in the current directory or one of its children.

Note: ls also has a -i option to get the inode associated with files.

Upvotes: 14

Cyrus
Cyrus

Reputation: 88563

Get inode with ext2/ext3/ext4 filesystem:

inode=262552
device=/dev/sda1
sudo debugfs -R "ncheck $inode" $device 2>/dev/null

Output (example):

Inode   Pathname
262552  /var/log/syslog

To show content of file:

sudo debugfs -R "ncheck $inode" $device 2>/dev/null | awk '/[1-9]/ {print $2}' | xargs cat

Upvotes: 14

clt60
clt60

Reputation: 63892

The portable but slow way is using the find -inum ..., for getting the filename for the given inode and in the next step use the found filename.

If you need just the content of the file (by the inode number), exists some file-system/OS specific solutions.

For the macOS it is simple as:

inode=48747714
eval "$(stat -s "/Volumes/volume_name")"
cat /.vol/$st_dev/$inode

E.g. In the OS X's HFS filesystem exists the pseudo directory /.vol, and you can use for accessing file contents by their inode number as:

/.vol/device_id/inode_number

the device_id is is obtainable from the stat for the given volume_name in the /Volumes, (check ls /Volumes).

Upvotes: 4

Inian
Inian

Reputation: 85550

If you have access to find with find (GNU findutils) and not the POSIX find, you can use its -inum option for it,

-inum n
       File  has  inode  number  n.   It  is normally easier to use the 
       -samefile test instead

Just use it along with the -exec option and open the file using cat, 

find . -inum 1346087 -exec cat {} \;

Assume inode value for my file sample.txt is as

ls -id sample.txt
1346087 sample.txt

Upvotes: 8

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