Questions specifically about Linux, as opposed to Unix-like systems in general, or to questions about a specific distribution or program.

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2
votes
1answer
15 views

(S/D)NAT over NF hooks

Could someone help on explaining the advantage of iptables NAT over the netfilter hooks. Say suppose, instead of using NAT if we create custom kernel module to bind handler with netfilter for PRE/POST ...
0
votes
0answers
13 views

I overwrote OSX with Linux by accident [migrated]

So here is what happened. I installed Ubuntu onto a flashdrive hoping to be able to dual boot Linux/OSX. I burned Ubuntu onto the flash drive on my desktop PC (windows 8.1) with universal USB ...
4
votes
1answer
36 views

what's the difference between page cache and buffer cache?

In linux OS, you can type command "echo 3 > /proc/sys/vm/drop_cache" to release memory, and you can type command "sync" to release the memory. And in linux kernel there are two kind of cache, one is ...
5
votes
1answer
1k views

What is SSTP vpn server and how can I run one?

I've read a couple of L2TP and PPTP tutorials on the net and there are just dozens of "running PPTP/L2TP on Linux" guides available out there and I successfully made packages like open-swan or pptpd ...
2
votes
1answer
32 views

Generic shared resource locking techniques - is flock the solution?

I need to implement a locking scheme so that multiple processes can share a set of resources, while a "special" process can obtain exclusive access to that set of resources. These are batch ...
1
vote
0answers
49 views

Trouble switching from DHCP to a static IP on Kali Linux

When I installed Kali Linux 64bit, I forgot to set up a static IP address, and now DHCP determines my address with my router. I have already modified /etc/hosts and /etc/network/interfaces to declare ...
1
vote
1answer
25 views

creating a custom service on ubuntu

I am setting up an ap called scumblr (https://github.com/Netflix/Scumblr/wiki) The final step calls for initiating the server using the following 3 commands: redis-server & ...
1
vote
0answers
74 views

Fedora 21 won't boot anymore; Computer wants me to perform MOK management

I have Fedora 21 installed. Last time it booted, I changed Gnome theme. Then I restarted and now I get following: If I select to continue boot, computer restarts and I get this window again. If I ...
2
votes
2answers
70 views

How to find a specific file and move it to a specific directory?

How to find a specific file, and move it to the specific directory /var/tmp? For example I want to find the file 0914_Jul-2014.gz. Remark, the file 0914_Jul-2014.gz, is under ~300 subdirectories: ...
14
votes
6answers
16k views

Check if folder is a mounted remote filesystem

What is the best way (reliable, portable, etc.) to check if a given folder is on a mounted remote (nfs) filesystem within a shell script? I am looking for a command that would look like: ...
1
vote
1answer
18 views

Alpine: work with some e-mails

How can I setup alpine to use more than one mail address? That SMTP Server parameter in config looks like an global. Can someone help me? NOTE: At least for both e-mails on the same server. Thanks.
0
votes
0answers
14 views

ipmitool set idrac mode

I have a DELL server R610, on this server there is a RHEL 6.4 This server has an idrac entreprise. I would like to configure the idrac from command line, avoiding reboot. I read on the man page of ...
1
vote
1answer
438 views

Why system call hooking produces different result everytime in Linux/Android 2.6.29?

I have implemented system call hooking for Android 2.6.29 kernel through a LKM module. I am tracing down one Android app for system calls. But interestingly, it returns different results every time I ...
4
votes
2answers
5k views

How to limit application memory usage?

I have spend 2 hours reading questions about this matter, and still there is some misunderstanding. I have this process: USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1452 0.4 1.8 ...
8
votes
2answers
353 views

How to limit the total resources (memory) of a process and its children

There are plenty of questions and answers about constraining the resources of a single process, e.g. RLIMIT_AS can be used to constrain the maximum memory allocated by a process that can be seen as ...
2
votes
5answers
5k views

How to install Linux on a Lenovo ThinkPad T400

I want to completely format my computer and replace my current OS with Linux. How should I go about doing this? Particularly, how do I handle finding all the device drivers I'll need? I'm using a ...
1
vote
0answers
33 views

X won't start on its own after kernel update [closed]

I built a Fedora 20 home theater pc following the Fedora 20 nVidia Drivers Install guide. It did work well. However after yum update all ( in which the kernel was updated to 3.17 ) the machine boots ...
5
votes
3answers
8k views

Adding a Column of values in a tab delimited file

How can I add a Column of values in a file which has a certain number of rows. I have a input file like this: Input file: SPATA17 1 217947738 LYPLAL1 1 219383905 FAM47E 4 77192838 SHROOM3 4 ...
9
votes
2answers
529 views

How do I force a user to change a password at the first time login using ssh?

I'm trying to force a newly created user to change a password at the first time login using ssh. For security reasons I want to give him a secure password until he logs in for the first time. I did ...
0
votes
1answer
489 views

VPN Setup Errors

I'm trying to install a VPN on one of our servers for use within my campus so that we can play some games, but I appear to be getting errors when I try to connect, as shown below. Not quite sure about ...
0
votes
0answers
14 views

install grub from grub bootable cd-rom

I want to install grub from grub bootable cd-rom. I found the instruction to make grub bootable cd-rom at ...
0
votes
1answer
40 views

Rename files in selected folder in Linux [duplicate]

Command for rename file as IMG0001 to 4R0001 in folder for f in *;do mv "$f" `echo "$f" | sed 's/IMG/4R/g' `; done AND I just want rename selected folder /tmp/2014/1201 (rename files) ...
1
vote
1answer
52 views

How to enable using commands on remote host using ssh without password?

i set up to use ssh between two hosts without password. ssh log in is working fine but execute commands failed with the below erro: **isn't allowed to be executed with process or redirect ...
1
vote
1answer
451 views

Determine whether kernel built-in driver supports a device

I'm trying to find a way to accurately determine whether all the hardware on some system has a valid driver installed either via a kernel module or built-in to the kernel. I'm working with RHEL 5.5 ...
0
votes
1answer
975 views

How to execute Netscaler commands through a remote machine via SSH connection

I have been trying to execute some NetScaler commands like "bind" & "unbind" through a Linux Box via an SSH Connection. Now the Problem is, Manually we are able to enter & execute commands on ...
0
votes
3answers
47 views

Setting Up VPN Practice/Service Without Access to Private Internet

I use Lubuntu 14.04. I've gotten concerned about encrypting my internet traffic after reading about the problems with public WiFi and intend to start using VPN. However, all my internet usage is on ...
7
votes
6answers
42k views

Why does find -mtime +1 only return files older than 2 days?

CentOS 5.9 I'm struggling to wrap my mind around why the find interprets file modification times the way it does. Specifically, I don't understand why the -mtime +1 doesn't show files less than 48 ...
2
votes
1answer
32 views

how does hdparm calculate spin-down times?

I have been trying various options with hdparm, like setting the spin-down time to 5 minutes withhdparm -S 60 and setting the APM to 1, but I end up getting a spin-down in less than 5 seconds... How ...
0
votes
1answer
30 views

Backing up Linux server to Windows domain

I'm maintaining a small Linux workstation/server in a Windows-domain-based environment. Apart from being in the same network, the Linux computer is not connected to the domain. Until now, I'm using a ...
0
votes
1answer
31 views

Make own graphical server [closed]

I had experience to work with framebuffer and found it pretty well to make own graphical applications. But the problem is that framebuffer is too slow. My goal: 1) Make a new tty which will work for ...
0
votes
1answer
43 views

How to copy a file with scp via another server

I have three machines. The local machine L, Server1 A, Server2 B. L is able to connect to A A is able to connect to B L is not able to connect to B I want to copy a file from L to B without ...
1
vote
0answers
23 views

A modern, easily configurable DE [closed]

I am looking for a linux desktop environment with modern look and feel and can be configured programmably (or has the capability of easily exporting and importing configuration) Does it exist?
0
votes
0answers
19 views

bootable usb creator without default bootloader

I want a program (a linux command is more preferable) to create a bootable usb drive but all the programs which I have seen have a default bootloader which they install but I want the bootloader in ...
56
votes
16answers
42k views

How can I get my external IP address in bash?

I need to find my external IP address from a bash script. At the moment I use this function: myip () { lwp-request -o text checkip.dyndns.org | awk '{ print $NF }' } But it depends on ...
3
votes
1answer
1k views

Kernel booting stops right after “Uncompressing Linux…”

I'm trying to bring up an ARM-based board. I've got U-Boot working but can't seem to get the kernel to load. Most of the time it only goes as far as: Starting kernel ... Uncompressing Linux... A ...
10
votes
6answers
43k views

How to remove all the files in a directory?

I am trying to remove all files and subdirectories in a directory. I used rm -r to remove all files, but I want to remove all files and subdirectories, excluding the top directory itself. For ...
2
votes
1answer
557 views

How to monitor per user disk usage in Linux

I have local disk with 2T capacity attached to a host. Nearly 60 user home directories are stored on this disk. Currently no disk quotas are enabled. I need monitor the disk usage of individual ...
1
vote
1answer
33 views

SELinux Sandbox Usage

What am I doing wrong in the following, from the man file and internet it looks like this is right. $ echo "hello world" 1> test $ sandbox -i test cat test /usr/bin/cat: test: Permission denied
1
vote
1answer
30 views

unable to open luks encrypted device (wrong password)

I'm using CentOS 7 with a luks encrypted root partition. Usually I have to type my password during boot, but sometimes the system doesn't accept it. It reacts as it was wrong, but it isn't. I did not ...
0
votes
1answer
45 views

Create A Script That Responds To A Password Prompt

I'm writing a shell script that will respond to a prompt. For example, when I execute a file, the executed file will then prompt the user with this: Please enter the password: Then I want the script ...
0
votes
2answers
3k views

Using port 587 with sendmail

I have been using sendmail to send out mails using internally available mail server. But currently port 25 is blocked for security reasons. I would like to know if there is a way to specify port ...
2
votes
1answer
228 views

Unable to use yum repos whether with baseurl or mirrorlist in CentOS 6.5

Since a couple of days, I'm unable to retrieve repositories data with Yum, in my CentOS 6.5 server. I did yum clean all a dozen of times, it emptied all but didn't solved the problem. I tried to ...
10
votes
1answer
3k views

Linux: What is a tainted kernel?

Under certain conditions, the Linux kernel may become tainted. For example, loading a proprietary video driver into the kernel taints the kernel. This condition may be visible in system logs, kernel ...
5
votes
2answers
5k views

iptables port-mirroring

I need to be able to get a copy of packets received on port 8001 to port 8002. I have tried the following but I get an error that --tee is undefined. sudo iptables -t nat -A PREROUTING -p TCP -s ...
0
votes
0answers
16 views

Gzip Mutliple files using single command [duplicate]

Want to Gzip my all the .csv files into a gzip file. I am using this command. gzip *.csv; Problem File contains '//' in its name that's why command is giving error. Error : - '//File.csv' is not ...
1
vote
3answers
2k views

PAM login permission denied

I have an OpenSuSE 12.3 machine and can't login to the box either on tty or via ssh. As soon as the user logs in the session terminates and in the message "login [1234] permission denied" is printed. ...
0
votes
2answers
2k views

Linksys AE3000 install on linux

I bought a Linksys AE3000 wireless adapter hoping I could use it on my Ubuntu 12.04 box. I found a website that walked through using it, but it didn't work. I edited rtusb_dev_id.c to add: and then ...
0
votes
1answer
3k views

How to install [ gcc ] without internet connection?

I simply ran yum install gcc this is what came up: ================================================================================ Package Arch Version ...
1
vote
0answers
17 views

Replace webcam transmission with an image from the hard drive

I'm working with an Android app installed in my Arch Linux using the emulator Genymotion. This app is not mine and I have not access to the source code, I'm just working with it. In some part of the ...
1
vote
0answers
13 views

Is it safe to use the -y and -Y flags to hdparm?

Is it dangerous to use the -y or -Y flag in hdparm during a write, or when the disk is still mounted, or will hdparm refuse to spin-down, or automatically sync and unmount?