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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1
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2answers
33 views

Need special validation for shell script

I want to create a bash script which will have lot of options while executing. # script.sh --dry-run --user <parameter1> --pass <parameter2> I heard about getopt option but looks like ...
0
votes
1answer
57 views

HDD Won't connect / system won't read it. Not sure what dmesg output means`

I have a hdd that I pulled from an old windows laptop, I don't think there's any information on it that I want to keep. I was going to format it to ext4 or something. Yesterday when I connected and ...
0
votes
0answers
16 views

Connected to wifi but no internet access

Unable to be pinged from other machines (other machine returns 'Request timed out') Unable to ping the router or any other device (returns 'destination Host unreachable) Unable to use the internet ...
1
vote
0answers
31 views

Is it possible to convert RHEL to CentOS?

The software vendor that we used has always specified that we should load RHEL on servers we've bought to run their software however they did start to accept CentOS and even now prefer it on new ...
2
votes
2answers
25 views

Managing settings from /sys directory in arch

I can manage /proc directory settings with sysctl and config files in /etc/sysctl.d but is there equivalent tool for the /sys directory? I want to change the I/O scheduler to bfq permanently. Should ...
2
votes
2answers
55 views

How do I prevent Ubuntu from writing ANYTHING to an external harddrive?

There are two reasons you would want to prevent Linux from writing anything to an external harddrive or USB drive when you plug it in: To recover accidentally deleted files from now "empty" part of ...
0
votes
0answers
27 views

what version of program X does not contain bug?

Suppose there's a bug in software (linux stuff) you need to use. You don't know if there are newer/older version of program without this bug. How do you find it out? This question occurred after the ...
3
votes
5answers
84 views

Get PID of process started by time

Say I run time ./a.out, then I can get the PID of time by the variable $!. But how do I get the PID of a.out? Of course, I could parse the output of ps, but I want a more elegant solution. I've ...
1
vote
1answer
79 views

Bash: Looping through a string

I have a variable Vmac that stores values of multiple MAC addresses, collected from wmic call as follows: Vmac=`wmic --delimiter="," --authentication-file=/path/to/file //IP-ADDR "Select ...
1
vote
0answers
30 views

Find who is connected to a Unix domain socket (Linux) [duplicate]

I have a Unix domain socket (for example /var/run/mysqld/mysqld.sock). I know there is open connection(s) to this socket thanks to lsof -U or ss -xa but I cannot find which process is connected to it. ...
1
vote
1answer
49 views

OpenVPN CLI for killswitch or connection fallback prevention

I'm using OpenVPN via command line to connect to my VPN on my current Linux distro since there is no GUI available (which had a killswitch checkbox). My problem is, I can't find any way to add a ...
0
votes
2answers
35 views

Difference b/w hardware time and system time [closed]

I want to know the exact difference between Linux "hardware time" and "system time". What time does the computer use? Is it Hardware or system?
0
votes
1answer
38 views

Parallelise rsync using GNU Parallel

I have been using a rsync script to synchronize data at one host with the data at another host. The data has numerous small-sized files that contribute to almost 1.2TB. In order to sync those files, ...
0
votes
0answers
41 views

Why doesn't Linux shutdown cleanly?

I'm running Linux Mint with LXDE on Dell Inspiron 1501. Whenever I issue poweroff command, or reboot or shutdown the computer via the graphical menus, it doesn't seem like a clean shutdown. In ...
2
votes
2answers
41 views

Best way of keeping clock accurate in LInux

I have researched many different of ways to accurately keep time in Linux, but there are so many programs and ways of doing it. I would like to know what you guys think is the best way to keep the ...
0
votes
0answers
21 views

Reinstall Win and save GRUB (on Debian)

I have dual boot on my computer. Windows and Debian 7.8 (wheezy) 64-bit. Now, I need to reinstall Windows. Which is the best way to do it?
1
vote
1answer
32 views

How can I cross compile the dd linux tool for arm?

I need to cross-compile a full version of dd because my device only has a busybox one that doesn't support many options. Where do I get the source for it? I've been looking on the kernel repo online ...
1
vote
1answer
27 views

NginX + PHP-FPM displays blank php pages

I have a problem where my server running NginX with php-fpm loads blank PHP pages (strangely except for my phpinfo.php file, which loads normally). If I put an index.html page in the same directory ...
2
votes
1answer
49 views

systemd mount 'rootfs' according to '/proc/cmdline'

SETUP Im running Debian 8 (jessie/testing) amd64 with systemd. On my system partition containing a btrfs filesystem, I do have the following layout: /dev/sda1 |-root |-root_snapshots/ ...
-2
votes
1answer
46 views

How to parse json output through shell / Python [closed]

I am running a curl command which gives me json response. Now I want to parse the response output to get the keys and corresponding values from the output or getting value for a particular key. I ...
0
votes
0answers
34 views

Not able to boot into ubuntu or windows

prerequisites you will need to know regarding my problem earlier I had Ubuntu 13 version, due to some unknown reason, when I restarted my computer to enter into windows it went directly to grub ...
0
votes
0answers
40 views

Cross compile GLIBC : error: Need linker with .init_array/.fini_array support

Whenever I call glibc configure with --prefix=/usr --with-headers=/var/tmp/ubuild.wandboard-armhf.build_dir/armv7a-hardfloat-linux-gnueabi/sysroot/usr/include --host=armv7a-hardfloat-linux-gnueabi ...
0
votes
0answers
68 views

How can I run script without root to sniff network (libpcap)?

I have a script (in ruby): require 'ffi/pcap' pcap = FFI::PCap::Live.new(:dev => "wlan0", :timeout => 1) pcap.loop() do |this,pkt| puts pkt.body end When I try to run the script , I get ...
3
votes
3answers
119 views

Understanding Bash's Command Substitution

I am trying to understand how exactly Bash treats the following line: $(< $FILE) According to the Bash man page, this is equivalent to: $(cat $FILE) and I can follow the line of reasoning for ...
0
votes
1answer
44 views

weird find command doing hard I/O operations and freeze my pc

I've noticed than many times my laptop freezes, checking the possible causes I found than it happens exactly when my disk is doing heavy work...now using iotop I found this: 29620 idle nobody ...
1
vote
1answer
65 views

Environment Variables not getting set in bash_profile

I have my bash_profile environment setting as follows: if [ `hostname` = "devoraebs01" ]; then echo `hostname -f` . /appl_top/deverp/appl/APPSDEVERP_devoraebs01.env When I log into this host, ...
1
vote
0answers
8 views

pannel applet wont spawn process

I am using Mate, with debian8, an this has never not worked, so I'm confused now. I have a custom applet (launcher), which reads: ssh user@ip When clicked it does nothing, ordinarily a terminal is ...
0
votes
0answers
16 views

TCP connections in SYN_SENT not visible with lsof

I have lots of connections in SYN_SENT: $ conntrack -L | grep -c 'SYN_SENT' conntrack v1.2.1 (conntrack-tools): 28100 flow entries have been shown. 14017 But I can't see which process(es) are ...
-1
votes
1answer
70 views

What are the commands which will work in unix but won't work in linux [closed]

Pls list the command or the scenario which will work in Unix but will never work in Linux
2
votes
2answers
197 views

monitor linux file systems using df

I use df -kh to get the file system usage, but the trouble is if there is any NFS mount failure in any of the boxes the command will hang. Is there a better way to monitor file systems other than df ...
2
votes
1answer
29 views

What is the best backup/restore tools for SUSE Linux system

All, Is there any tools like Norton Ghost for Linux to help backup and restore SUSE when necessary? Thanks.
0
votes
0answers
21 views

Compiling a loadable kernel module(Debian/Ubuntu)

This question is a follow up of this one. I am trying to compile the ELF loader as an individual LKM and use it as a standalone application(replacing the original module within the base kernel sounds ...
0
votes
2answers
18 views

Create a symbolic copy of another directory that has it's own local data

I have a directory foo that contains files and directories. I want to create a new directory foo_0311 that contains the same files as foo (and sees updates when the files change), but that allows by ...
1
vote
0answers
33 views

Multiple Windows recovery image deployment via Linux PXE server?

Is the following scenario feasible: A laptop repair workshop currently using multiple, physical hard disk caddies containing various Windows 7 / 8 recovery images for repairing various laptop models ...
0
votes
1answer
34 views

NFS File Mounting error in centOS

I'm trying to mount server filesystem using NFS in centos. But I'm getting Connection timed out error. Below are the steps I followed. At server side: [centos@ip-172-31-46-199 landingzone]$ sudo vi ...
3
votes
0answers
17 views

Calling ioctl on same file descriptor from two different processes [migrated]

If I call ioctl (this is a custom kernel driver to read/write Altera registers), and another process calls ioctl on the same file descriptor while the first ioctl is still executing, does the first ...
3
votes
1answer
72 views

Get kernel source: apt-get install vs apt-get source

I'm looking forward to download a Linux Kernel to get to know how to modify it and how to compile it. I am using Debian distribution and I'm interested in the Debian-modified Linux Kernel rather than ...
2
votes
2answers
42 views

Is shell parent of all the processes in linux

I have been trying to understand shell scopes and environment in depth. I have been reading about how if we do export VARIABLE=VALUE it will be available in subshell. So I wanted to ask a question I ...
0
votes
2answers
50 views

Accessing port 8080 on a server without using port 8080 for my SSH connection

I'm running a program that lets you interact with it in the browser. To do this you run the program and open "localhost:8080" in your browser (if 8080 is the right port). However, I'm running the ...
1
vote
1answer
19 views

Incoherent measures with perf record

While trying to get some measures from HPC with perf record, I'm getting some incoherent values, I think. I'm using the next command to get some mesures: perf record -T -F997 -e ...
0
votes
0answers
41 views

Best way to transparently redirect traffic to proxy

I've implemented a wireless router using hostapd on Debian Wheezy running on a Banana-PI. To access the internet, this router is attached to another network that I haven't any control of via ethernet. ...
3
votes
2answers
46 views

How to disable network access for a user?

Trying to disable the network access for the user: [root@notebook ~]# iptables -I OUTPUT -m owner --uid-owner tempuser -j DROP [root@notebook ~]# ip6tables -I OUTPUT -m owner --uid-owner tempuser -j ...
0
votes
1answer
92 views

Linux Bash Script Ideas [closed]

I have been given the task of creating a shell script to show my proficiency in scripting. I am really struggling with ideas on what to do. I would like to create something that is relevant and could ...
0
votes
0answers
34 views

open ssl client giving error routines:SSL23_WRITE:ssl handshake failure:s23_lib.c:188:

On connecting to my application (a ssl server) by using command openssl s_client -host 127.0.0.1 -port 5028 -cipher EXPORT -debug -state I am getting error like CONNECTED(00000003) ...
1
vote
1answer
19 views

Behaviour of priority inheritance in mixed systems

If I have a realtime linux system, but with certain subsystems not being realtime. What happens if I use priority inheritance with certain synchronization objects that are shared between both the ...
0
votes
0answers
13 views

Send raw IP packets to a server, forward them to their destination addresses, and give responses back to clients

A similar question was asked here. But I'm not sure I need OpenVPN for what I'm going to do. I have an Android device with a TUN network interface and capture IP packets. Then I'd like to forward ...
0
votes
0answers
15 views

Linux - is it possible to limit VFS cache usage on a per-process basis

I'm trying to investigate performance degradations while running background copy operations (using dd to write or read large disk-images). Is it possible to limit VFS cache usage for a single ...
1
vote
1answer
57 views

Understanding rc.local and troubleshooting

I (new to linux) am attempting to add a command to the boot up that will execute an application. The application accepts parameters and has simple output of what it is doing. To troubleshoot it, how ...
0
votes
0answers
12 views

Changing static on SuSE linux

I have recently received a Linux Suse Ent server that has an active service agreement attached with it. The service requires an VPN connection so I have to change the IP, Default gateway. I have ...
0
votes
2answers
37 views

Run script and not lose access to prompt / terminal

I am running jmeter by launching the .sh script, once I do that I cannot start using the prompt again unless I ctrl-z, ctrl-c, or the script ends in some other way. How can I launch that script and ...