05-05-2009
While some of the examples are rather interesting, and reading the wikipedia text on Fork Bomb was also entertianing, I'll supply a command that I thought was rather innocent.
This happened about 12 years ago.
My first day back from a two day unix taining class, I was experiencing a problem (I don't remember exactly what), but I attributed it to bad permissions.
Then, while logged in as root, and at the root directory, I executed the following:
chmod -R 777 *
This changed the permissions of every file on the hard drive. This WAS what I intended. I though it was a good idea to do this, until....
Less than a minute later, my phone started ringing.
It seems unix doesn't like to have it's permissions played with, and reacted rather defensively. With the exception of the console terminal, users that logged off could not log back on. Similarly, networked printers stopped working, although the one printer attached directly did work.
Fortunately, this happened at about 4:40pm on a Friday. We were a 9-5 M-F office, so I only killed the last twenty minutes of the workweek. Not a very productive time period anyway.
Unfortunately, I killed my entire weekend fixing it. I didn't have a good mksysb tape to use and had to 'figure out' a variety of things to fix it.
8 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
I want to know if there is a way to send unix commands thru FTP from a mainframe to kick off Autosys Jobs. I just need to send a command from the mainframe to UNIX and have UNIX execute that command. (2 Replies)
Discussion started by: skammer
2 Replies
2. UNIX for Dummies Questions & Answers
hi, can i have a unix like environment where i can do things like chmod, shell scripts and etc.. in redhat instead of the GUI that redhat ofters? (4 Replies)
Discussion started by: yls177
4 Replies
3. News, Links, Events and Announcements
http://www.computerhope.com/unix.htm
http://www.linuxdevcenter.com/linux/cmd/ (0 Replies)
Discussion started by: devotedsinner
0 Replies
4. Shell Programming and Scripting
This is my first time using this forum. My question is simple. I need a book that has the commands code for Linux, if there is such a book, of course.
Thank you (1 Reply)
Discussion started by: ropapi
1 Replies
5. UNIX for Dummies Questions & Answers
I'm working on further developing my Unix skills and I'm just curious what some of the experienced admins out there would consider to be 10 essential commands every admin should know. (12 Replies)
Discussion started by: Arkitech
12 Replies
6. Shell Programming and Scripting
I have many files with info about soft, installed on remote machines.
I need to compare this file with template (soft than must be installed) and output file must content info about software that's not installed.
template.txt
software_name1
software_name2
software_name3.1
... (14 Replies)
Discussion started by: cintlt
14 Replies
7. UNIX for Dummies Questions & Answers
Hi All
I have found that few basic commands in unix have the same syntax in linux as well. I need those commands which differ on Linux platform, with some more advanced options..
For example... awk, sed, tr ... and some more commands with advanced options. I am trying to search on the linux... (1 Reply)
Discussion started by: vee_789
1 Replies
8. UNIX for Beginners Questions & Answers
Hi all,
I'm new to UNIX world and new to this forum. As I observed there are lot of commands that needs to be remembered in UNIX programming. I'm into DevOps and can anyone please tell me what are all the important commands that are useful for DevOps Engineer.
NOTE: Please correct me if my... (3 Replies)
Discussion started by: maxlink
3 Replies
LEARN ABOUT CENTOS
pam_console_apply
pam_console_apply(8) System Administrator's Manual pam_console_apply(8)
NAME
pam_console_apply - set or revoke permissions for users at the system console
SYNOPSIS
pam_console_apply [-f <fstab file>] [-c <console.perms file>] [-r] [-t <tty>] [-s] [-d] [<device file> ...]
DESCRIPTION
pam_console_apply is a helper executable which sets or resets permissions on device nodes.
If /var/run/console.lock exists, pam_console_apply will grant permissions to the user listed therein. If the lock file does not exist,
permissions are reset according to defaults set in console.perms files, normally configured to set permissions on devices so that root owns
them.
When initializing its configuration it first parses the /etc/security/console.perms file and then it searches for files ending with the
.perms suffix in the /etc/security/console.perms.d directory. These files are parsed in the lexical order in "C" locale. Permission rules
are appended to a global list, console and device class definitions override previous definitions of the same class.
ARGUMENTS
-c Load other console.perms file than the default one.
-f Load other fstab file than the default one (/etc/fstab).
-r Signals pam_console_apply to reset permissions. The default is to set permissions so that the user listed in /var/run/console.lock
has access to the devices, and to reset permissions if no such file exists.
-t Use <tty> to match console class in console.perms file. The default is tty0.
-s Write error messages to the system log instead of stderr.
-d Log/display messages useful for debugging.
The optional <device file> arguments constrain what files should be affected by pam_console_apply. If they aren't specified permissions are
changed on all files specified in the console.perms file.
FILES
/var/run/console.lock
/etc/security/console.perms
/etc/security/console.perms.d/50-default.perms
SEE ALSO
pam_console(8)
console.perms(5)
BUGS
Let's hope not, but if you find any, please report them via the "Bug Track" link at http://bugzilla.redhat.com/bugzilla/
AUTHORS
Nalin Dahyabhai <nalin@redhat.com>, using code shamelessly stolen from parts of pam_console.
Support of console.perms.d and other improvements by Tomas Mraz <tmraz@redhat.com>.
Red Hat 2005/5/2 pam_console_apply(8)