Permissions, flags and attributes

Change uid and gid

usermod -u 2005 foo
groupmod -g 3000 foo

find / -group 2000 -exec chgrp -h foo {} \;
find / -user 1005 -exec chown -h foo {} \;

usermod -g <NEWGID> <LOGIN>

Read ttyUSB0

chmod a+rw /dev/ttyUSB0

Cd rom access

chmod u+s /usr/bin/wodim

End-to-end file access without read directory

chmod 711 <folder name>

Sticky Bit

chmod +t <folder or file name>

Restore execute bit to chmod tool

Information from

setfacl -m u::rwx,g::rx,o::x /usr/bin/chmod
/usr/lib64/ld-linux-x86-64.so.2 /usr/bin/chmod +x /usr/bin/chmod
cp --attributes-only /usr/bin/ls ./new_chmod; cat /usr/bin/chmod > ./new_chmod
install -m 755 /usr/bin/chmod ./new_chmod
rsync --chmod=ugo+x /usr/bin/chmod ./new_chmod
python -c "import os;os.chmod('/usr/bin/chmod', 0755)"

Capabilities

Information from

Get all files with capabilities

getcap -r /

Set capabilities in systemd Unit

CapabilityBoundingSet=CAP_NET_BIND_SERVICE
AmbientCapabilities=CAP_NET_BIND_SERVICE

ACL

Set default permissions

setfacl -d -m u::rwx,g::r-x,o::r-x /home/test/

Remove default permission

setfacl -k /home/test/

Remove permission

setfacl -x user_name /home/test/

Recursive

setfacl -R

Remove all acl

setfacl -bn /home/test/

View permissions

getfacl

Umask

umask

Chattr

Make immutable

chattr +i <file name>

Only append

chattr +a <file name>

Kernel compress/decompress

chattr +c <file name>

Ignore when dump

chattr +d <file name>

Security remove

chattr +s <file name>

Remove with save data

chattr +u <file name>

Sync on disk

chattr +S <file name>

Show the file attributes

lsattr file_name