How to check umask for all users under Linux?

Question

Under AIX I can check the umask for all users with:

cut -d : -f 1 /etc/passwd | while read ONELINE; do lsuser -a umask "$ONELINE"; done

But how can I check the umask setting for all users under Linux? (su to every user and then umask command? Are there any better ways for it?)

UPDATE1:

It's not the best to su to all users, because on some RHEL servers the default shell for a few user is halt/shutdown..:

shutdown:x:6:0:shutdown;asdf;asdf;F:/sbin:/sbin/shutdown

so if I su to the user... then the server shuts down?

UPDATE2: I created a bounty for a non-su based answer.

I have already mentioned for avoid system user ($3 > 500), means check above UID 500 — Rahul Patil, Jul 11 '13 at 15:43
again: I need to check umask for all users, not excluding system users :) — gasko peter, Jul 11 '13 at 17:02
we can check for valid shell, what you think ? , means if shell is other that /bin/bash , then we can skip that user. isn't it ? — Rahul Patil, Jul 12 '13 at 13:41

slm · Answer 1 · 2013-07-15T07:06:28.717

The umask is typically set system wide through the config file: /etc/login.defs:

$ grep UMASK /etc/login.defs 
UMASK           077

This value can be overridden but typically is not through either /etc/bashrc, /etc/profile and/or by the users in their $HOME/.bashrc (Assuming they're using Bash).

If you grep for "umask" in those aforementioned files you'll also notice this on RHEL boxes:

$ grep umask /etc/bashrc /etc/profile
/etc/bashrc:    # By default, we want umask to get set. This sets it for non-login shell.
/etc/bashrc:       umask 002
/etc/bashrc:       umask 022
/etc/profile:# By default, we want umask to get set. This sets it for login shell
/etc/profile:    umask 002
/etc/profile:    umask 022

Digging deeper:

/etc/bashrc

# By default, we want umask to get set. This sets it for non-login shell.
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then
   umask 002
else
   umask 022
fi

/etc/profile

# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then
    umask 002
else
    umask 022
fi

So at least on RHEL system's the umask is either 002 if your UID is greater than 199, and 022 otherwise (system accounts).

For Ubuntu and (probably) Debian-based systems, you should do this in ~/.profile, which has the default value commented at the top of the file for you to uncomment and modify on a per-user basis. — code_dredd, Jun 05 '18 at 19:24

score 11 · Accepted Answer · edited May 16 '22 at 10:20

11

You can check using (execute as root) :

for user in $(awk -F: '{print $1}' /etc/passwd); 
do 
    printf "%-10s" "$user" ; su -c 'umask' -l $user 2>/dev/null
done

To avoid checking system user do :

for user in $(awk -F: '( $3 >= 500 ){print $1}' /etc/passwd); 
do 
    printf "%-10s" "$user" ; su -c 'umask' -l $user 2>/dev/null
done

OutPut:

ram       0022
shyam     0022
suraj     0022
vinayak   0022
javed     0022

edited May 16 '22 at 10:20

noraj

340

answered Jul 11 '13 at 14:23

Rahul Patil

24,711

1

ok, thanks, but are there any ways to check the umask without "su"ing to the user? – gasko peter Jul 11 '13 at 14:38
if you have manually set , say in ~.bashrc then you can grep into this file. – Rahul Patil Jul 11 '13 at 14:49
It could be set in many places... that's why grepping is not the best solution – gasko peter Jul 11 '13 at 14:51
then we have to check in many place – Rahul Patil Jul 11 '13 at 14:52
it should be better , if you have set umask in per user in common file eg .bashrc – Rahul Patil Jul 11 '13 at 15:03
On Ubuntu 16.04, your first script outputs the word "root" and then freezes for me. – Borea Deitz May 23 '21 at 19:51
Freezing happened to me as well, looks like it expects some input. Hitting enter twice got it to print the next user... over and over again. – mrfreester May 06 '22 at 19:13

How to check umask for all users under Linux?

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