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35
votes
4answers
10k views

How do I run a command as the system administrator (root)

I need to run a command with administrative privileges. Someone said I should run a command as root. How do I do this?
29
votes
7answers
15k views

How do you kick a benign user off your system?

I was googling this a bit ago and noticed a couple of ways, but I'm guessing that google doesn't know all. So how do you kick users off your Linux box? also how do you go about seeing they are logged ...
25
votes
2answers
8k views

Is it possible to rename a Unix user account?

I installed Ubuntu on a computer that is now used by somebody else. I renamed the account with her name, but it only changes the fullname, not the user name, which is still displayed in the top right ...
23
votes
2answers
768 views

Why did a new user inherit files from a deleted user?

So I had to do an exercise in a book as homework. First you had to create a user like: useradd -c "Steven Baxter" -s "/bin/sh" sbaxter Then you had to add some files to the /home/sbaxter directory: ...
20
votes
3answers
39k views

How to make Fedora user a sudoer?

I want to give a Fedora user sudo privileges. How do I do that?
13
votes
4answers
797 views

Is it possible for a sysadmin to eavesdrop on his/her users' terminals?

When logged in to a machine, I can find out each user's pseudo-terminal device(s) from the output of w. Being a sysadmin, is it possible for me to eavesdrop on this terminal without the user being ...
13
votes
2answers
26k views

How can I change a user's default group in Linux?

Being new to Linux administration, I'm a little confused about the following commands: useradd usermod groupadd groupmod I've just finished reading the user administration book in the Linux/Unix ...
12
votes
11answers
1k views

Concern about logging in as root overrated?

For personal linux on my personal notebooks, I've usually set my environment to autologin as root even under X or lower runlevels. I've found my workflow is very pleasant and fast, without any ...
9
votes
1answer
5k views

How can I configure cgroups to fairly share resources between users?

There used to be a kernel config option called sched_user or similar under cgroups. This allowed (to my knowledge) all users to fairly share system resources. In 2.6.35 it is not available. Is there a ...
8
votes
5answers
4k views

How to know if /dev/sdX is a connected USB or HDD?

How can I know if /dev/sdX is a local HDD or usb key ? best doing this without root privileges. OK , udevadm helped a lot: For local HDD: udevadm info --query=all --name=sdb | grep ID_BUS E: ...
8
votes
2answers
4k views

How to know reason of a process going to sleep state and wake it up?

When I do 'top' , I see my perl script process in 'S' state. Is there a way to know, what is making this perl process go in sleep state and ways to wake it up? Any way to debug to give more insights ...
8
votes
4answers
401 views

What are your best practices and future plans for deploying unixoid desktops?

I have been setting up Linux desktops for a non-profit radio observatory. For me, this was the first time I had to think about "deploying" several identical machines, centralizing login, home ...
7
votes
3answers
2k views

What is the point of the 'operator' user?

Many un*x systems ship with a user account named 'operator'. What is the purpose of this account? Do some systems actually make use of this account, or is this more of a historical legacy? Have you ...
7
votes
3answers
22k views

Alternatives for “lsof” command?

In many cases "lsof" is not installed on the machines that with I have to work, but the "function" of lsof would be needed very much (ex. on AIX). :\ Are there any "lsof" like applications in the ...
7
votes
3answers
506 views

Linux Bulk/Remote Administration

Beside our internal IT infrastructure, we've got around 500 Linux machines hosting our services for the on-line world. They are grouped in a bunch of clusters like Database A-n, Product A-n, NFS, ...
7
votes
3answers
181 views

Linux/Unix variant for training system administrators

Is there a Linux/Unix based operating system used for training sysadmins? Some bugs would be deliberately included in the system and the training candidate is supposed to solve all of them. It should ...
6
votes
5answers
450 views

What are the recommended ways of defending a remote *nix install from a hamfisted admin?

Once in a while (often a long while), I have a difficulty where I execute a command that completely screws up a Linux machine. Most recently, I accidentally mounted-again the root partition (thinking ...
6
votes
6answers
838 views

How to prevent a mistaken rm -rf for specific folders?

I think pretty much people here mistakenly 'rm -rf'ed the wrong directory, and hopefully it did not cause a huge damage.. Is there any way to prevent users from doing a similar unix horror story?? ...
6
votes
3answers
941 views

How to tell when a computer is idle?

I have a computer that is only used some of the time, and I was was wondering if there was a way to have it turn itself off after a period of inactivity. Here's the tricky part, if I was just ...
5
votes
5answers
900 views

Why is it recommended to create a group and user for some applications?

Most of the time, when installing a program from source it is recommended to create a new user and a new group and give /usr/local/<myapp> the recently created user and group ownership. Why is ...
5
votes
5answers
382 views

Which tasks to learn and which books to read to become more skilled at Unix/Linux internals? [closed]

I recently interviewed at a major company and did well on programming questions such as: "What is the time complexity of quicksort? What is the opposite in C of malloc? What is the opposite in ...
5
votes
1answer
603 views

What is the routing behaviour when two or more default routes?

I have two ISP at the time, connected to the same machine. I added both of them in the routing table as default. However, only one connection is used. $ route Kernel IP routing table Destination ...
5
votes
0answers
96 views

Logging violations of rules in limits.conf [duplicate]

I'm trying to log the details of the programs that where failed due to the limit cap defined in the limits.conf. My initial plan was to do it using the audit system. The idea was to track the system ...
4
votes
2answers
142 views

Simple Templating for Config Files

I need to manage a growing set of similar-but-different ASCII files. ( It so happens that they're Apache VirtualHosts, but that's not particularly relevant. ) For each production website, the ...
4
votes
1answer
91 views

Distributing Updates to VirtualBox Images with (Bandwith) Efficency

I'm currently responsible for a lab of machines that all need to run the same virtual machines. I want to automate my current setup of distributing VirtualBox virtual machines via rsync (erasing any ...
3
votes
4answers
215 views

How do you work with old servers?

I've recently fallen into doing more work on LAMP servers, which is pretty new to me. At first it wasn't a problem migrating my preference files, but as I've grown and learned more, my preferences ...
3
votes
4answers
2k views

How can I assign an initial/default password to a user in Linux?

I found a guide that explains how to set a user's password. I'm trying to automate it and send an e-mail to the user like: userid created with password XYZ. request to change the initial password. ...
3
votes
2answers
3k views

How to see complete list of processes in top

When I do 'top', I learn that there are many processes running out of which many are in sleep state. I need to see complete snapshot of all processes at that point. the 'top' is able to show listing ...
3
votes
1answer
898 views

How to get Oracle java 7 to work with setcap cap_net_bind_service+ep

I am trying to grant the java executable the right to open ports below 1024 on Linux. Here is the setup /home/test/java contains the Oracle Server JRE 7.0.25 CentOS 6.4 Here is what getcap ...
3
votes
2answers
1k views

SELinux: Can I disable copying of certain files?

Please excuse me if this is too basic and you're tempted to throw an RTFM at me. I want to prevent users from copying certain files while granting them read access to the same files. I thought this ...
3
votes
1answer
45 views

How does iptables recognize packet state?

Consider these two sets of rules: Set A -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT -A INPUT -j REJECT -A OUTPUT -j ACCEPT Set B -A INPUT -m conntrack --ctstate ...
3
votes
1answer
64 views

What is a program I can use to mess up a GNU/Linux system in an automated way?

I once ran across a program that, when run on a GNU/Linux system, would automatically screw up something about the system. Maybe it would corrupt the users database. Maybe it would mess with the boot ...
3
votes
1answer
957 views

How to disable root account on openSUSE?

Is there a way to disable the root account completely on openSUSE so you can administer your system like the way you would do in Ubuntu?
3
votes
1answer
252 views

How can I set a directory maximum size?

Is there an easy way to cap the size of a directory? I don't think there is but just wanted to make sure. I would like to set max directory sizes for some user home dirs as well as some other dirs, ...
3
votes
1answer
575 views

How do I add a local user to a box that uses LDAP authenticaiton?

I'm working with a box that uses LDAP for user authentication. However, I need to add a local user to run some services and I don't want non-person users junking up the LDAP directory. Does anyone ...
2
votes
3answers
237 views

How can I see which package manager is running?

I'm on Debian 6.0.5 (squeeze) and every now and then I see the following icon in the notifications area of the GNOME2 pannel: but black instead of red. It reads A package manager is working. Usually ...
2
votes
3answers
9k views

How do I add an entry to my crontab?

I am using crontab for the first time. Want to write a few very simple test cron tasks, and run them. $crontab * * * * * echo "Hi" doesn't produce anything. crontab */1 * * * * echo "hi" says ...
2
votes
1answer
48 views

Manage another Linux installation on another partition in the same computer

How can I manage (install packages, manage packages, check for updates and the like) for another Linux installation on another partition in the same machine? I would be doing this from Ubuntu, and ...
2
votes
1answer
282 views

Should I use useradd or adduser?

I am trying to add a new user to the system. I am confused though which command to run: useradd or adduser?
2
votes
3answers
5k views

CentOS 6 - nameserver entry in resolve.conf resetting after restarting network services?

In /etc/resolv.conf, I've changed the nameserver line to a new IP address. After saving and exiting, I run service network restart. I then go open /etc/resolve.conf again and see that the IP address ...
2
votes
2answers
182 views

How do I check active crons?

I'm trying to hunt down a cron job (or the equivalent) which I know is running, but I can't find it in the default cron files for my system (FreeBSD / Linux / BSD). How can I tell which ones are ...
2
votes
4answers
449 views

Hardware and software inventorying

Objective Collect hardware and software information from lab computers, respecting students' privacy. Type of information to collect Examples: System memory Bash verion JVM version Operating ...
2
votes
2answers
43 views

Reassign users to a single group

Right now one of our server is setup such that all users are in their own group. Is it possible to reassign them to a single group and then allow each user READ only access to other user's ...
2
votes
0answers
57 views

How to specify a daemon shutdown command with upstart?

In an upstart configuration how do I define what command should be used to shutdown a server. Lets say I have daemon that has two seperate processes. startup.sh - to start the server shutdown.sh ...
1
vote
1answer
167 views

How to prevent users from renaming files while providing write permissions on Linux [closed]

For some special purpose, I want to prevent non-root users of the Linux Server from changing or renaming the filenames. However, they can modify and write to the contents of the file. How to do this ...
1
vote
2answers
94 views

Does DM-Crypt partition look like random noise?

If I format partition with dm-crypt does its entry in partition table suggest somehow that this partition is encrypted or for someone from outside it looks like regular partition with random noise ...
1
vote
2answers
3k views

How to expire a password? (For inital account creation)

I've often created temporary passwords for users for my own development machine for initial id creation. For other environments, I've seen admins have the ability to have a password show as expired ...
1
vote
2answers
2k views

mounting to non-empty directory, then later deleting original files

I have some unused space on my disk, and decided to use a little of it to create a separate /var partition. There might be an easier way to do this, but my idea is to copy the existing /var ...
1
vote
3answers
142 views

How to clean up my desktop?

Now, I see that my desktop running rhel 5.6 has run out of space. Now I need to clean it up. There must be some unintentional files adding up. What I would like to be able to do is list the files in ...
1
vote
2answers
167 views

Browser-based front-end to linux

I'd like to ask if anything like this exists. A browser-based tool for looking at a Linux system, managing it, and helping newbies diagnose problems. What I'm thinking of is something like this : ...