39 lines
929 B
Markdown
39 lines
929 B
Markdown
|
---
|
||
|
|
title: "hard links"
|
||
|
|
tags: [ "basics", "links" ]
|
||
|
|
---
|
||
|
|
|
||
|
|
A hard link is one file which exists in multiple locations.
|
||
|
|
|
||
|
|
Each file has an ID, which is kept on the hard disk's partition.
|
||
|
|
Each hard link has the same ID, because they are the same file.
|
||
|
|
This ID is called the 'inode'.
|
||
|
|
|
||
|
|
Create a file, and a hard link:
|
||
|
|
|
||
|
|
```bash
|
||
|
|
fortune > $file_1
|
||
|
|
mkdir -p x/y/z/
|
||
|
|
ln $file_1 x/y/z/$file_2
|
||
|
|
```
|
||
|
|
Have a long look at the file with the `-l` flag, and check the inode with `-i`:
|
||
|
|
|
||
|
|
```bash
|
||
|
|
ls -li $file_1 x/y/z/$file_2
|
||
|
|
```
|
||
|
|
|
||
|
|
Since they are the same file, you can make a change to one, and it changes both:
|
||
|
|
|
||
|
|
```bash
|
||
|
|
fortune | tee x/y/z/$file_2
|
||
|
|
cat $file_1
|
||
|
|
cat x/y/z/$file_2
|
||
|
|
```
|
||
|
|
|
||
|
|
# Danger Zone
|
||
|
|
|
||
|
|
- hard links will not work on directories, only standard files and fifos.
|
||
|
|
- `git` will destroy and remake files, so it will not respect hard links.
|
||
|
|
- Files cannot have a hard link on another disk partition, because the inode is stored on each partition.
|
||
|
|
|