Unix puzzle

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Across
  1. 2. it displays username of a current user
  2. 5. print current working directory
  3. 7. displaying lines of text or string which are passed as arguments on the command line
  4. 9. make new directory
  5. 13. use to display user manual
  6. 14. changes passwords for user account
Down
  1. 1. calendar command
  2. 3. print the top n number of lines
  3. 4. to create a copy of the contents of the file
  4. 6. print the number of users who has logged in
  5. 8. change the access mode of a file
  6. 10. remove files
  7. 11. displaying and creating files
  8. 12. list your files
  9. 15. printing new line