permissions

Permissions

ls -l shows bits
First bit says if directory
Next three user
Next three group
Next three other
Two ways to change permissions using chmod include symbolic and octal
- user, don't add anything
- For recusion use -R after setting permission using chmod
- Can do user and group at the same time
- Capital X is for directories to have execute rather than files
- group use g
- other use o
- all use a
- These commands can be chained for example chmod ugo-r file to remove read for user group and other, there is also a for all
  - Remove other chmod o-xr
  - octal permissions
- read=4, write=2, execute=1
- One can use which to find the location of an executable file and change the permissions
Use -s to execute as owner of file
- One can use +s or -s for the stickybit on symbolic notation
- Use 4 character, First character, 4=user, 2=group, 7=other
- Write Protect
- Symbolic use +t

default permissions on new files and folders
not persistent by default
Default permissions folder 777, file 666
Number for umask subtracts from default permissions based on hex notation
Change umask with umask 0022
Default umask is set in bashrc
- If user and group are the same a seperate nmask can be used
- Difference is privleged vs normal user
- One can use umask in scripts

groupadd
getent group
- cat /etc/group
- chown user:group file/directory One can do :group to just do a group
usermod -G <group> <user> to add a user to a group
Have to log out and back in after privleges change