Linux-Ubuntu (Essential Commands)
  1. File management
    1. Directory Structure (Filesystem Hierarchy)
    2. ls -- list directory contents
    3. file -- display file type
    4. wc - print word counts
    5. touch -- change file access and modification times
    6. cp/scp -- copy files/directories
    7. mv -- move files/directories
    8. rm -- remove files/directories
    9. mkdir -- make directories
    10. rmdir -- remove directories
    11. find -- search files/directories
    12. ln -- make links
    13. tar -- manipulate tape archives
    14. gzip/gunzip -- compression/decompression
    15. df -- display free disk space
    16. du -- display disk usage statistics
  2. File permissions
    1. chmod -- change file modes
    2. chmod -- change file ACLs (Access Control Lists)
    3. chown -- change file owner and group
    4. chgrp -- change group
  3. Users and Groups
    1. Users
    2. Groups
  4. Processes
    1. ps
    2. top
  5. Scripts
    1. Special Characters
    2. Redirection/Pipe operators
    3. crontab
  6. Text Editor
    1. cat -- concatenate and displays files
    2. more -- displays files
    3. less -- displays files
    4. head -- displays the first lines of files
    5. tail -- displays the last lines of files
    6. vim
  7. lsof (LiSt Open Files)
HowTos
  1. Clear systemd journal logs
  2. List and delete a file or a directory with a name starting with dash (-) characters
Appendix
  1. Notes
  2. Shell
  3. GNOME 3 Desktop
  4. System info
  5. Manage Packages
  6. User profile
  7. Linux aliases
  8. /var/log/*
References

Books

Linux Bible: The comprehensive, Tutorial Resource

Linux Bible: The comprehensive, Tutorial Resource

Authors: Christopher Negus
Publisher: Wiley; 9 edition (April 2015)
ISBN: 978-1118999875
Linux Command Line and Shell Scripting Bible: The comprehensive, Tutorial Resource

Linux Command Line and Shell Scripting Bible: The comprehensive, Tutorial Resource

Authors: Richard Blum, Christine Bresnahan
Publisher: Wiley; 3 edition (January 2015)
ISBN: 978-1118983843

Linux: The Complete Reference

Authors: Richard Petersen
Publisher: McGraw-Hill/Osborne; 6 Edition (2008)
ISBN: 978-0071492478

OS X El Capitan: The Missing Manual

Authors: David Pogue
Publisher: O'Reilly Media; 1 edition (November 2015)
ISBN: 978-1491917954
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