Skip to main content
OverflowAI is here! AI power for your Stack Overflow for Teams knowledge community. Learn more
20 votes

What program in Linux computes the hash of the input password when you log in?

No specific binary does the hashing; it's done by a library call crypt(3). So, in theory, any program (even a perl script) can generate the hash. e.g. perl -e 'print crypt("hello","\$...
Stephen Harris's user avatar
15 votes
Accepted

Running GNU screen through SSH, the shell is not a login shell?

From the man pages of GNU screen: -s program sets the default shell to the program specified, instead of the value in the environment variable $SHELL (or "/bin/sh" if not defined). This can ...
aviro's user avatar
  • 5,622
8 votes

What program in Linux computes the hash of the input password when you log in?

when we input the credentials in the login prompt, the hash of the password is computed and then that hash is compared with the hash stored somewhere, and if I am not mistaken that "somewhere&...
Gilles 'SO- stop being evil''s user avatar
3 votes

What program in Linux computes the hash of the input password when you log in?

The binary responsible for computing the hash of the input password is typically part of the authentication system and is not implemented by the kernel. In most Linux distributions, this is handled by ...
Swapnil's user avatar
  • 47
3 votes
Accepted

SSH Key issue - Fedora 38

SSH does some security restrictions for your own security. While everything under ~/.ssh seems ok, stan $HOME is too open at 775/rwxrwxr-x per your .. at your .ssh directory ls output. If logged as ...
Rui F Ribeiro's user avatar
2 votes

I am Unable to access to root user in oracle linux server

You've broken the sudoers file, and so sudo will refuse to allow any access. If you have the root password then you can use it to fix the problem: su - visudo If you haven't, then you're going to ...
Chris Davies's user avatar
2 votes

How to configure a shutdown at the xth wrong entered password?

2023 solution working on ubuntu with pam_faillock (pam_tally2 is deprecated): Careful, you can lock yourself up: Editing pam files will take effect instantly and it is more likely than not that you ...
Triptiloop's user avatar
2 votes

What are the side effects of having several UNIX users share one UID?

I've used such an alias for the root user so that I can specify a different login shell (and home directory). So my zoot user is root, but with zsh as the login shell and my home directory as the home ...
raf's user avatar
  • 171
2 votes
Accepted

Anyone know what these all these user sessions (see post) might be?

The first result I came across in google for "man who" was https://linux.die.net/man/1/who This appears to match the manpage (man who) on many of my machines, including CentOS and RedHat. It ...
Stephen Harris's user avatar
2 votes
Accepted

Lightdm multi screen arrangement

Generating the command for the adequate configuration Install the graphical tool arandr: beside allowing to change the current users's layout easily, it can save this current layout in the form of a ...
A.B's user avatar
  • 36.9k
2 votes

How do I set up a login shell with arguments?

How can I pass arguments to my login shell? You can't. You need to make a new executable that launches your intended executable with the options you want.
sina bala's user avatar
  • 481
2 votes
Accepted

Can cURL get the Username and Password Fields From a Website?

Curl doesn't do the HTML parsing for you in this case. You need to do it yourself; this suggests maybe trying to do this all in a shell script is not the easiest route to take. I'd probably go an ...
sina bala's user avatar
  • 481
2 votes

Can cURL get the Username and Password Fields From a Website?

No. curl only retrieves data. It is not made to parse the response body at all. For any sorts of automating logins to websites in scripts, I recommend using Python and the requests module as well as ...
Hermann's user avatar
  • 6,207
2 votes
Accepted

Keyboard layout skipped during installation and changes don't persist in Linux Mint

What caused the issue? This issue was caused by my keyboard. I have the corsair K57 Wireless RGB. When I start the installer with the keyboard connected via the USB dongle, the menu to choose the ...
DasMoorhuhn's user avatar
1 vote
Accepted

Issue with using SSH with jump host

[email protected]:12345 is not a valid destination. The right syntax is either [user@]hostname or ssh://[user@]hostname[:port]. Try this: ssh -J [email protected] ssh://[email protected]:12345 -p does not apply ...
Kamil Maciorowski's user avatar
1 vote

How to display text for non-interactive login shell

~/.bashrc and the equivalent system-wide one if any (generally /etc/bash.bashrc) is normally not read by non-interactive invocations of bash. It is also not read by interactive login shell invocations,...
Stéphane Chazelas's user avatar
1 vote

disabling the direct login for super user (common super user account) and other users (not having the sudo access) need to switch as super user

sudo is your solution; sudo su is not. We have a common superuser account ("cmn_usr") with sudo access, and separate normal user accounts ("nml_usr") without sudo access. For ...
Chris Davies's user avatar
1 vote

How to clone CentOS 7.7 installation on another disk?

Clonezilla is capable of cloning the whole disk to another disk. I think that's what you need in this case.
Turdie's user avatar
  • 111
1 vote
Accepted

Debian "Login Incorrect" for all users before entering password

Having just recovered from this state, this is what I did; Boot using the Debian Live installer, and go into recovery. Load the existing installation in recovery Mount all relevant drives, in my case ...
Jademalo's user avatar
  • 121
1 vote

Debian "Login Incorrect" for all users before entering password

So, somehow your libcrypto.so doesn't work with the rest of your system. Maybe an interrupted upgrade? Maybe it was something manually patched and excluded? Hard to guess. Anyway, libcrypt is involved ...
Marcus Müller's user avatar
1 vote
Accepted

How to lock down Ubuntu linux so that only the active user can log in

By default, Ubuntu doesn't allow anyone to log in remotely – you'd need to install a server for that (for example, for an SSH server, the openssh-server package), and then activate it. So, unless you'...
Marcus Müller's user avatar
1 vote

Anyone know what these all these user sessions (see post) might be?

"system boot" is the time/date of the most recent system boot. "Runlevel 5" is the time/date of the system entering multi-user mode.
waltinator's user avatar
  • 4,931
1 vote

log out from slim, or slim restart results in blank screen for several minutes

The slim.conf file looks fine to me. Since you did not share the value of your DISPLAY variable I'll try to do some guess work. The format of DISPLAY variable is [host]:<display>[.screen]. I ...
tukan's user avatar
  • 4,951
1 vote
Accepted

I don't acquire supplemental groups at login

From the comments to the question, it is clear that you are connecting to the remote system over a preexisting shared SSH connection using SSH connection sharing. When you use SSH connection sharing (...
Kusalananda's user avatar
  • 336k
1 vote

I am Unable to access to root user in oracle linux server

If you don't have the root password, but your user account is in the wheel group (or sudo group for Debian/Ubuntu), there is one more thing to try: pkexec visudo It should prompt for your password (...
telcoM's user avatar
  • 97.9k
1 vote

Difference between Login Shell and Non-Login Shell?

Almost all the answers here are missing on how to check a login shell (only Timothy is close but still technically incorrect). echo $0 is not a surefire way to check it. You can see this simply by ...
Taylan's user avatar
  • 111
1 vote

How to switch between users on one terminal...completely (XDG environment variables (re)set)?

If you have root/sudo access and need to fully impersonate another user without knowing or changing their password, if your Linux distro is modern enough to support it you should use: sudo machinectl ...
PolyTekPatrick's user avatar
1 vote

Script for testing SFTP login status?

If by chance, your backup script is based on Python, you might want to check out check_sftp, a so-called active check brought with Checkmk. It has the specific use-case of checking SFTP servers. Since ...
riha's user avatar
  • 113

Only top scored, non community-wiki answers of a minimum length are eligible