permissions http://enos.itcollege.ee/~edmund/osadmin/eng/file-permissions/file-permissions.pdf http://permissions-calculator.org/ http://askubuntu.com/questions/152001/how-can-i-get-octal-file-permissions-from-command-line https://www.tutorialspoint.com/unix/unix-file-permission.htm Midnight Commander sudo apt update && sudo apt -y install mc && sudo apt-get clean to run: mc config files ~/.config/mc/ alternatives: Far https://en.wikipedia.org/wiki/Far_Manager Norton Commander https://en.wikipedia.org/wiki/Norton_Commander + add - removing = sets the designated permission(s) u user g group o others sudo chmod -R u+rw /path/ sudo chmod -R /path/ get permissions in octal at CLI: stat -c '%A %a %n' /path/file http://linuxcommand.org/lts0070.php u g + r chmod - w file1 file2 ... o = x a u – user (owner) g - group o - others a - all r - read w - write x - execute you can use multiple permissions at once: chmod ug+rw file chmod g+w,o+rx file SetUID user must have also execute bit chmod u+xs file chmod u+xs folder nothing will happen e.g. chmod 4700 file - allow execute also for user SetGID group must have also execute bit chmod g+xs file chmod g+xs folder files in such folder have same group as the folder Sticky bit others must have also execute bit chmod o+xt owner group others chmod read write execute read write execute read write execute 0777 4 2 1 4 2 1 4 2 1 0755 4 2 1 4 0 1 4 0 1 0500 4 0 1 0 0 0 0 0 0 ---------- 0000 no permissions at all ---------x 0001 eXecute --------w- 0002 Write –-------wx 0003 Write, eXecute –------r-- 0004 Read -------r-x 0005 Read, eXecute -------rw- 0006 Read, Write -------rwx 0007 Read, Write, eXecute –--------t 1000 sticky –-----S--- 2000 setgid –--S------ 4000 setuid umask ----- opposite value of permission default: folders: 777 files: 666 umask 022 folders: 777-022=755 files: 666-022=644 nano ~/.profile umask 022 source ~/.profile write permission to the group: umask 007 folders: 777-007=770 files: 666-007=660