Wongwingjosqwqdz

 In addition to these beautiful answers I want to mention a small but probably important difference The command chmod 755 file is equivalent to chmod 0755 file If we run this command on a file which has the SETUIDbit or SETGIDbit set, it will remove the SETUID/SETGIDbit chmod x file will leave the SETUID/SETGIDbit untouched We can see this  #3 644 means that files are readable and writeable by the owner of the file and readable by users in the group owner of that file and readable by everyone else 755 is the same thing, it just has the execute bit set for everyone The execute bit is needed to be able to change into the directoryThe 2 in front of 775 causes the group who is the owner of /var/www to be copied to all new files/folders created in that directory There are also other options then 2 0 setuid, setgid, sticky bits are unset 1 sticky bit is in place 2 setgid bit is in place 3 setgid and sticky bits are in place 4 setuid bit is in place 5 setuid and Understanding File Permission...