What is umask in Linux?

HowToForge ^ | 01 April 2020 | Staff

[ShadowAce]

Tech Ping

[central_va]

$su - root
#cd /
#rm -rf *

This corrects everything.

[ShadowAce]

I figured a non-virus thread may be good for people.....

[Red Badger]

UMASK is the Chinese Command to put you MASK BACK ON!...............

[Scrambler Bob]

#rm -rf *

This corrects everything.

If you first declare * = Pelosi

[PastorBooks]

“rm -rf *”

I see what you did there...

(Lest someone new to Linux reads this and tries it, that command will wipe your entire drive.)

[zadox]

Thanks, it was nice to have an otcv -other than corona virus- post. I’ve always just created the file then used chmod to change it to whatever I need.

[PastorBooks]

“UMASK is the Chinese Command to put you MASK BACK ON!...............”

:-)

And ‘cd ~’ means STAY HOME.

[Red Badger]

And ‘cd ~’ means STAY HOME.

CD ~ CHANGE DIRECTION!..................

[ken in texas]

Years ago someone in my group did that on one of the machines in our test lab. Fortunately, he worked in another city and was spared physical punishment.

[Campion]

Let’s just say, after you do that, you won’t be wasting any more time browsing FR.

[central_va]

I remember when making daily backups was done to protect against stupidity and not as a defense against nefarious destruction caused by virus attacks or break ins.

[Bob434]

ok don’t know how to ping everyone at once- but here3’s a totally off topic question, Just a quick response is fine if anyone knows how to do this- i hope you won’t mind?- it’s firefox related-

When I’ve got several tab open- sometimes I’ll accidentally click/drag on a tab and yank it off the main page so that it’s now in a separate window- a ‘new window’- This is totally annoying- (I have a mouse gesture program that allows me to quickly switch tabs by a mouse gesture- saves a ton of time- but now that the tab is now in it’s own window- i can’t do that)

is there a way to get it back onto the nest of tabs on main window?

[Bob434]

[[$su - root
#cd /
#rm -rf *]]

I did that and now the police are outside the door- what did you do to me?

[ShadowAce]

Yes, there is.

WARNING--It's so simple you'll hate yourself...

Drag the new window back onto the tab bar of the original window.

[ken in texas]

Yup. Fortunately, the machines were all in a test lab for my group, no production stuff, but a couple folks had work interrupted.

[Bob434]

i tried that- Not working for some reason- i’ll keep trying

[Bob434]

uggh- now it’s working- didn’t work before- Thanks for the suggestion- it’s just one of those little irritating things that drive a person nuts- and i didn’t know how to fix it- Thanks for the solution- i don’t know why it wasn’t working before- I think what i was doing (it was awhile ago) was trying to grab the minimized window onto the open main window (that doesn’t work- just tried it again)- gotta grab open new window tab and drag to open main window-

Thanks again-

[zeugma]

The permissions discussed in the article above aren't the only attributes you can set on a file/directory. There are also extended attributes that give you a little finer-grained control over files. You can even create a file that is immutable even by the root user.

In the following, lines that begin with "$" are the commands entered. Lines beginning with "###" are my comments.

$ id
uid=1000(zeugma) gid=1000(zeugma) groups=1000(zeugma),...
### The username is zeugma, as is the group name
$ touch myfile
### I created 'myfile'
$ ls -l 
total 0
-rw-rw-r-- 1 zeugma zeugma 0 Apr  1 11:36 myfile
### Yup, 'myfile' was created
$ rm myfile 
### I can delete it
$ touch myfile
### Create myfile again
$ ls -l
total 0
-rw-rw-r-- 1 zeugma zeugma 0 Apr  1 11:37 myfile
### Yup. the file was created
$ lsattr myfile 
-------------e-- myfile
### lsattr shows additional file attributes
$ chattr +i myfile
chattr: Operation not permitted while setting flags on myfile
### Ooops. Can't do that as a regular user
$ sudo chattr +i myfile
[sudo] password for amp: 
### Looks like the SuperUser can do it. Adding "i" to a file makes it read-only.
$ lsattr myfile 
----i--------e-- myfile
### now we see the 'i" in it's attributes
$ ls -l 
total 0
-rw-rw-r-- 1 zeugma zeugma 0 Apr  1 11:36 myfile
### looks the same with an 'ls' command though...
$ rm myfile
rm: cannot remove 'myfile': Operation not permitted
### looks like I can't delete it, even though I own it, and the file is "rw"
$ sudo rm myfile
rm: cannot remove 'myfile': Operation not permitted
### Not even SuperUser can remove it!
$ sudo chattr -i myfile 
### Removing the readonly bit
$ rm myfile
### I can now delete the file
$ ls -l
total 0
### Yup it's gone.