How to clean junk file on Linux

Background

With the help from the friend in LCPU, I learnt and make a disk clean days before. As there was limited left space for me on my VPS, I had to learn how to clear unnecessary files, though I had never done it before. I am here writing the skills about cleaning junk file on Ubuntu.

How to clean junk file

First of all, we need to install a useful tool called ncdu which can help you find the largest junk file on your system.

apt install ncdu

Then use it by:

ncdu

You will find which file you need to delete. In my case, I need to clean the following junk file.

Clean apt cache

sudo apt clean

Clean yarn cache

yarn cache clean

Clean snap cache

sudo snap clean

Clean log file and set the limit space for log

journalctl --disk-usage # see how many space log file uses
vim /etc/systemd/journald.conf

[Journal]
SystemMaxUse=500M # set the max disk usage for log
RuntimeMaxUse=200M # set the max disk usage for log when running

sudo systemctl restart systemd-journald
sudo journalctl --vacuum-time=7d # delete old log file and keep the recent 7days log file

Outcome

Before clean

After clean