Useful Linux commands and tricks. Mostly for Ubuntu-based distributions.
Search text in files
Search text in files with grep:
# Search in the working directory # -r means "recursive" grep -r "your text" # Search in the given directory, i.e. /etc/ grep -r "your text" /etc/
Check free disk space
Display disks and available free space:
# -h displays sizes in a more human-readable format: MBs, GBs, etc. df -h
Check size of directory
# -h displays sizes in a more human-readable format: MBs, GBs, etc. # -s give summary; by default it prints out information for all dirs du /path/to/your/dir/ -s -h # Without dir calculates size of the current working dir du -s -h
Check device memory
Check free and used memory, both RAM and SWAP:
# -h displays sizes in a more human-readable format: MBs, GBs, etc. free -h
Clean up unnecessary packages, including intermediary. Do it rarely, mostly when /boot/ is overfilled with obsolete Linux kernels and related files.
sudo apt autoremove
Guide for creating and changing SWAP file in Ubuntu.