Clear All Log Files

Guide on safely clearing or deleting log files in Linux systems to free up disk space without breaking running services.

The Risks

❌ *Never run `rm -rf /var/log/`* Deleting the files* themselves can break services (like Apache, Nginx, or Syslog) because they still hold the file handle open. They will stop logging until restarted.

✅ Correct Method: Truncate the file content to zero bytes while keeping the file properly in place.

Method 1: The Safe "Truncate" Loop

This command finds all files in /var/log ending in .log (or all files) and empties them.

sudo find /var/log -type f -name "*.log" -exec truncate -s 0 {} \;

truncate -s 0: Sets file size to 0 bytes.

Method 2: Systemd Journal (journalctl)

On modern systemd systems (Ubuntu 16.04+, Debian 8+), most logs are stored in the journal binary format.

Check Disk Usage

journalctl --disk-usage

Vacuum (Clear) Old Logs

Retain only the last 100MB:

sudo journalctl --vacuum-size=100M

Retain only the last 2 days:

sudo journalctl --vacuum-time=2d

Method 3: Logrotate (The Proper Way)

Instead of manually deleting logs, configure logrotate to do it automatically.

Edit configuration: /etc/logrotate.conf
Ensure you have settings like:
```
weekly
rotate 4
compress
```
Force a rotation now:
```
sudo logrotate -f /etc/logrotate.conf
```

Method 4: Removing Old Archives

If you have many access.log.1.gz, syslog.2.gz, etc., you can safely delete these compressed archives as they are connected to nothing.

# Delete all gzipped log archives
sudo find /var/log -type f -name "*.gz" -delete

Emergency Space Recovery

If your disk is 100% full:

Clean Apt Cache:
```
sudo apt clean
```
Remove Old Kernels:
```
sudo apt autoremove --purge
```
Clear Thumbnail Cache:
```
rm -rf ~/.cache/thumbnails/*
```