The command that allow us to change the file owner and group is: chown The command that allow us to change the file permissions is: chmod The correct value for the permission rwxr--r-- is: 744 The correct value for the permission ----w---x is: 021 The file that contains the list of information for all the users is: /etc/passwd In the /etc/passwd each line contains one user informations In the /etc/passwd each line contains informations separated by : and has 7 columns per line The command that allows to remove the execute permissions for all the users is: chmod a-x The commmand that allows to print the last 10 lines of a file is: tail The command that allows delimits by : and returns the 1st field is: cut -d: -f1 The command that searches the files that their names starts with img in the whole system is: find . -type f -name "img*" The command that searches the files that their names ends with .img in the while system is: find . -type f -name "*.img" The command that allows to print the environnement variables is: printenv