I have respectively noted about some compression commands and how to use symbol link to point to file:
- [Linux] Compression, Encrypted compression, Split compression, Decompression
- [Linux] Use “ln” Command to Create Symbol Link and Hard Link Files
Today, what I want to record is how to “compress the file and contain the symbol link“
It will be problematic to use the zip command to compress directly
As a demonstration, I already have an “A folder” pointing to myself infinitely today
Originally, in the A folder, there will be both “A folder’s own symbol link” and a file named test.txt.
If we go to the next level of the symbol link, we will also see this folder and a test.txt.
In this way, it can be proved that the symbol link really points to the original A folder.
So if we directly use the zip command to compress, what will happen to the symbol link folder?
mkdir B
zip -r B/A.zip A/
unzip B/A.zip -d B/In this way, we compressed a copy of the original A folder and decompressed it in the B folder. Now we use the du command to see the difference between the two folders?
du A/Output:
This is the original folder. Since the symbol link underneath points to itself, it does not take up space. And what about the decompressed ones?
du B/A/Output:
very impressive! And each symbol link folder is now a separate folder, so it will take up a lot of space.
The reason why it looks good today is because there is only one test.txt file under my folder, if I put it in the data today Are there pictures and videos in the folder?
This is the danger of compressing folders with symbol links.
Use the -ry parameter
Back to the topic, when using the zip command to compress a folder with a soft link, we should add the -ry parameter.
rm -r B/*
zip -ry B/A.zip A/
unzip B/A.zip -d B/So what is the difference?
du A/Output:
Here is the original file. The following is the newly unzipped folder A:
du B/AOutput:
As you can see, the symbol link is effective.