per default – different distributions set different accessrights for newly created files.

it seems „per default“ – every file creation process would set the access rights to ugo+rwx (all rights for all users and groups) – umasks overwrites this „default“ setting to make things more secure.

user@suse:~> touch newfile
user@suse:~> ll|grep newfile
-rw-r--r-- 1 user users          0 11. Mai 12:08 newfile
user@suse:~> umask
0022
-> octal: 0/0/2/2 -> this translates to binary: 000/000/010/010

user@debian:~$ touch newfile
user@debian:~$ ll|grep newfile
-rw-r--r-- 1 user user    0 May 11 12:09 newfile
user@debian:~$ umask
0022
-> octal: 0/0/2/2 -> this translates to binary: 000/000/010/010

[user@centos ~]$ touch newfile
[user@centos ~]$  ll|grep newfile
-rw-rw-r--. 1 user user   0 11. Mai 12:09 newfile
[user@centos ~]$ umask
0002
-> octal: 0/0/0/2 -> this translates to binary: 000/000/000/010

user@suse:~> umask 077
user@suse:~> touch newfile_umask_077
user@suse:~> ll|grep newfile_umask_077
-rw------- 1 user users          0 11. Mai 12:32 newfile_umask_077

per default every – Debian/Ubuntu/RedHat/CentOS create for every new user – a new group with the same name – SUSE12 does NOT.

so while under debian/ubuntu a new user with „username“ automatically belongs to a newly created group „username“ and his home is set to username:username

per default every new user in SUSE12 is member of a common group called „users“. Ask SUSE why 😀 (this allows every user basically to „look into“ all other user’s home directory – not sure if this is wise and why)

on SUSE12 the /home/username is set to username:users

make umask settings permanent:

You can set umask in

# Debian/Ununtu/Suse
echo "umask 022" >> /etc/bash.bashrc

# CentOS/RedHat
echo "umask 022" >> /etc/bashrc

or

# all distros
echo "umask 022" >> /etc/profile

for all users.

By default most Linux distros will set it to 0022 (022) or 0002 (002). (src)

manpages:

set file mode creation mask – umask.man.txt

Links:

https://www.cyberciti.biz/tips/understanding-linux-unix-umask-value-usage.html

https://www.kernel.org/doc/man-pages/

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