Command-line tools
Articles of this type from all portals.
- apt autoremove LinuxWhat apt autoremove removes, why packages become 'no longer required', and how to check the list before removing anything.
- df (disk free) LinuxHow to read df output, why Use% can reach 100% before Avail is zero for normal users, and how to check inodes with df -i.
- Disk usage with du and ncdu LinuxHow to find what fills a Linux disk with du and the interactive ncdu, with options that stay on one file system.
- DISM (Deployment Image Servicing and Management) WindowsWhat DISM is, the /CheckHealth, /ScanHealth and /RestoreHealth commands, and how DISM and SFC work together to repair Windows.
- File permissions: chmod and chown LinuxHow Linux read, write and execute permissions work, what 755 and 644 mean, and how to change owner and mode safely.
- Finding large and old files with find LinuxHow to use find to list big or old files on Linux, preview them safely and delete only what you checked.
- journalctl and the systemd journal LinuxHow to read logs with journalctl, check how much space the journal uses and shrink it safely with --vacuum options.
- lsblk and block devices LinuxHow to list disks and partitions with lsblk, read sizes, file systems and mount points, and identify a new disk safely.
- rsync LinuxHow rsync copies and synchronises files, what the trailing slash changes, and how to test with --dry-run before --delete.
- SFC (System File Checker) WindowsWhat sfc /scannow does, how to read its results, where the CBS.log is and when to run DISM first.