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Questions tagged [linux]

These questions are about Linux in general -- NOT specific to a particular distribution. If the question just happens to be in a Linux environment, please specify your Linux distribution in the body of your question, but do NOT use the /linux tag.

1
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0answers
11 views

Does the Linux Page Cache (Buffer Cache) only cache the files' clusters (pages) or does it also cache the Inodes (metadata)?

The Linux-Kernel implements a Page Cache (often also called Buffer Cache) to speed up the file systems of the underlying storage devices. Does the Page Cache only cache the pages or clusters of files ...
1
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1answer
40 views

How can I fix “sh: apt-get command not found”?

I just succeded to run pulpino on Zedboard FPGA and I managed to boot an OS on it. But, the problem that there no apt-get command. I checked the following: $ uname -a Linux buildroot 3.18.0-xilinx #1 ...
60
votes
6answers
106k views

Allowing a user to let listen to a port below 1024

I need to allow a user (different from root) to run a server listening on port 80. Is there any way to do this?
10
votes
1answer
679 views

Is “Cached” memory de-facto free?

When running cat /proc/meminfo, you get these 3 values at the top: MemTotal: 6291456 kB MemFree: 4038976 kB Cached: 1477948 kB As far as I know, the "Cached" value is disk ...
1
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0answers
16 views

to set the default permissions on files under a specific folder

Scenario: We're receiving the below files from upstream which is a mainframe system. -rw-rw---- 1 s36748 xyz 293 Jun 6 19:20 CSJ_H_20190606.csv -rw-rw---- 1 s36748 xyz 3284 Jun 6 19:20 ...
0
votes
2answers
56 views

How to mount sda hard drive

We are trying to take a backup from one of the hard drive, it has 4 TB, Previously it was configured in raid. I found this using blkid command. blkid /dev/sda TYPE="isw_raid_member" I am not able to ...
0
votes
0answers
15 views

What is the difference between using keysims and keycodes in defining mappings with xbindkeys?

According to the man page for xbindkeys (emphasis mine): To specify an associated key, you can use xbindkeys --key or xbindkeys --multikey and put one of the two lines in the configuration file. ...
28
votes
3answers
87k views

How to read the local DNS cache contents?

I know that on Windows I can issue ipconfig /displaydns and I see the local DNS's cache content. How can I list the DNS's cache content in Linux? I would like to get as much as cross-distro solution ...
17
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3answers
174k views

Correct way to mount a hard drive

I have a 2nd hard drive SDB but not sure how to mount it under linux. mount -a did not seem to mount all. Also would like to mount this RO for recovery.
0
votes
1answer
73 views

How to hide script from process list in Linux?

I have a script in linux: #!/bin/bash export DISPLAY=:1 value=$(</home/pace/Desktop/BODVersion.txt) cd $value gnome-terminal \ --tab -t "CTCLManager" -e " sh -c 'sleep 1s; ./startapp ...
1
vote
1answer
50 views

Setting 'DF'-bit in ip-header inside pcap file

There is some .pcap-file with fragmented ip traffic. I replay this file with tcpreplay, but also I need to replay it with DF (don't fragment) bit set in some packets. I supposed that tcprewrite will ...
2
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1answer
29 views

DNS issues on a single Wifi - Linux Mint 19.1

I'm having DNS problems with one WiFi network which I've been using for a long time. I tried to do an hotspot with my phone and everything worked as normal, so the issue is only on that network. ping ...
0
votes
1answer
15 views

turbostat - Why sometimes RAMWatt is about 100 in idle?

By using turbostat command we can check the power consumption of RAM. ex: CPU%c6 ... PkgWatt RAMWatt 96.56 ... 64.43 93.12 CPU @ c6 state more than 95%, I think the system is in idle....
0
votes
1answer
35 views

Getting Error with system() in perl

' Number found where operator expected at ./scripttemp.perl line 5, near ""sed -i -r "4" (Missing operator before 4?) String found where operator expected at ./scripttemp.perl line 5, near "}" ...
0
votes
1answer
16 views

how to remove/update the existing user without losing permissions on files already created [closed]

How to remove/update the existing user without losing permissions on files already created in a windows file server? if anyone can help with the unix/linux command
1
vote
1answer
1k views

Chromium web browser: user specific /etc/chromium/policies/managed/ policy file

I am helping with the set up of a Linux-based Library kiosk thin client solution. We are using Chromium for the web browser, which is launched by a shell script with various command line options. ...
0
votes
1answer
33 views

Bind DNS Server

enter code hereI am setting up my primary DNS server. The reverse lookup appears to work fine, it is the forward lookups that seems to be the problem. Here are my configurations files. /etc/default/...
2
votes
1answer
68 views

Linux From Scratch: Error while compiling binutils 2.32

I am working on Linux from Scratch and currently, I am on this page. While compiling binutils-2.32, I am getting this error: lfs@pop-os:/mnt/lfs/sources/binutils-2.32/build$ ../configure --prefix=/...
0
votes
1answer
1k views

Parsing xml into array using xmllint

I have xml file with multiple <db> elements, I need to extract attributes from each node and do some work on them. IS it possible to load them to array, using ksh and xmllint ? This is what I ...
1
vote
0answers
19 views

Is mounting an ext4fs (any fs for that matter) on subdirectory of a linux FUSE file system allowed?

I have a FUSE mount point at /home/abc/fuse/ and it has few a directories and files inside. /home/abc/fuse/foo.txt, /home/abc/fuse/bar.out, /home/abc/fuse/logs/ etc. Now I want to mount an ext4 fs on /...
0
votes
1answer
17 views

Why does a file's Inode number change and nothing else?

Today I noticed that tripwire thinks that some Apache configuration files changed yesterday. I know I did not make any changes to those files. Looking at the info, it shows that only the Inode number ...
0
votes
2answers
39 views

Replacing output with awk or sed

So what I've been trying to do is replace a certain output in bash with awk. But I can't seem to get it to work. I'm trying to replace the $6 output from "uptime" to 'user' instead of 'users'. How can ...
0
votes
0answers
5 views

Yocto adding multiple system services to recipe file

I am modifying a Yocto .bb recipe file to add and enable 3 systemd services in my image. Below shows the bottom of my recipe file with just two services added and enabled. This works! app1.service is ...
0
votes
0answers
16 views

bastion server with MFA don't work with proxycommand

I have a bastion server with enabled MFA using google-authenticator service. But I cannot use proxycommand through my bastion: $ ssh -vvv -i ~/.ssh/file.pem user@ip -o "proxycommand ssh -q -W %h:%p ...
1
vote
0answers
57 views

USB don't show on fdisk

I have a USB and for some reason i can't access it. On fdisk -l i don't see the USB, also not show on gparted or anywhere.... I don't remember the format of the usb. Kernel version: 4.15.0-50-...
1
vote
1answer
16 views

how to get packets log which are dropped by rp_filter=1

I do need a log of packets which are dropped by rp_filter ... how to do this logging ? which logs how to enable.
-3
votes
2answers
43 views

Add single file into a TAR

I have a tar archive named backup.tar. I want to add a file named sshd.conf into this tar archive.
2
votes
2answers
1k views

What does bash do when it receives the SIGINT signal?

This page says the following: When Bash is interactive, in the absence of any traps, it ignores SIGTERM (so that `kill 0' does not kill an interactive shell), and SIGINT is caught and handled (...
1
vote
1answer
33 views

Linux user with numerical name found and can't find who is it

Simple and fast question: kevin@pc:/usr/lib/jvm$ ls -l total 8 lrwxrwxrwx 1 root root 25 Feb 20 17:31 default-java -> java-1.11.0-openjdk-amd64 lrwxrwxrwx 1 root root 21 Apr 23 20:34 java-1.11....
1
vote
2answers
6k views

boot hangs at “Started Update UTMP about System Runlevel Changes.”

i've just upgraded my debian system from debian stretch to debian sid which not stable version so after i finished upgrading and try to reboot my system hangs at "Started Update UTMP about System ...
1
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0answers
31 views

qemu kvm VM needs to access Internet by bridging wifi

I have some Qemu KVM virtual machines (CentOSs and Debians mostly) and my host is an Ubuntu. I configured the VMs networks with virtio virbr0, and I also made it work by creating a virtual interface, ...
1
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0answers
26 views

Can't use pip in red hat 4.4.7

I've installed python 3.7 and pip, but running pip gives me an error: pip3.7 install django pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available. ...
0
votes
1answer
1k views

Mysql database didn't connect through sqlyog or any other mysql software?

I can connect to a MySQL server through a browser and also I can show all database list through PuTTY. But when I try to use sqlyog or running the mysqldump command through PuTTY it shows this error: ...
0
votes
1answer
32 views

Can user space memory make the system go haywire?

So I was reading How Linux Works by Brian Ward. In it, he says, the user-space applications going bad will not wreck the system. Figure 1-1. General Linux system organization There is a critical ...
0
votes
2answers
58 views

Linux command to delete this

I want to delete this kind a pattern in my text file [-.(D_)-]. I did with sed and awk but no results. basically i want to delete anything that comes between [- & -] along with these characters ...
0
votes
1answer
35 views

How to properly write a string to a named pipe and the difference between echo and printf

Problem: I need to send a command to a named pipe and need to ensure only the command is sent and not any errant or "fat-fingered" characters. Example: I have been using the following: echo "...
0
votes
0answers
28 views

What is the useful case of trapping shell script's EXIT? [closed]

Trapping a shell script exit can be demonstrated like this. #!/bin/bash trap "ls -al" EXIT count=1 while [ $count -le 3 ] do echo "This is $count" sleep 1 count=$[ $count + 1 ] done ls -al ...
3
votes
2answers
1k views

How do I route a spare network interface through an SSH tunnel?

I just bought a Raspberry Pi and I am wanting to route an ad hoc wireless network interface fully through an SSH tunnel that was created using another wireless interface. I want to do this so that I ...
3
votes
1answer
1k views

Can I use a parallel port as a CUPS input device?

I have an old piece of a hardware that does diagnostics on medical equipment. It prints out results over a parallel port. Is there any way to have CUPS accept jobs from a parallel port and redirect ...
0
votes
1answer
34 views

Fix the output of uptime

So I've been experimenting with Bash not too long ago, and I want to manipulate the output from the "uptime" command. I managed to change the output of up x minutes to 0:05 for example if the up time ...
1
vote
1answer
28 views

My /usr directory is 100% full. Unable to download packages

What kinds of files are okay to delete in /usr directory without blowing up the server?? Is it possible to increase the size of /usr directory without blowing up server?
0
votes
1answer
20 views

Limit a VPN server's services to VPN connections only

I have a jump server and I want to put it behind a VPN, I do not want to deploy a separate VPN server and put my jump server behind it. I thought of installing OpenVPN directly onto my jump server and ...
0
votes
1answer
19 views

Postfix send e-mail on behalf of G Suite

I have a domain registered on G Suite and I'm building a app that needs to send Transactional email such as password recovery and email verifies. The smtp for gmail has a low quota for that. I need to ...
29
votes
4answers
45k views

How to check drive temperature on Linux?

I have used of hdparm -n and smartctl -A but it always seem to be a "per drive" technique as a drive may answer for only one of these tools. So, is there a standard way to get the drive temperature ...
0
votes
1answer
15 views

Getting the last output from a stuck screen session

I have a very stuck screen session - I can see it in screen -ls, it shows as attached, but I can't detach it re-attach it, not even with "screen -D -RR". Trying the detach and re-attach in separate ...
0
votes
0answers
9 views

Can i remove Android-x86 only by deleting its folder?, installed above another Linux distro?

By accident i made an installation of Android-x86 in my /dev/sda1 partition, i have an installation of Fedora in that partition (luckily i did not reformatted the partition). So i did a reboot and ...
0
votes
1answer
33 views

Why does delete work but not arrow keys in terminal? [duplicate]

In a linux terminal I use "cat > file.txt" to make a file one line at a time. What I find is that per-line the delete key works but the arrow keys insert escape codes rather than moving left and ...
0
votes
0answers
14 views

How to copy ownership and permissions using rsync but not the files

I am using AWS CodeDeploy to copy files from git to the server. It can't overwrite the files, so I have to move the files to another temp location and then it moves the files from the repo to the ...
0
votes
1answer
32 views

Linux unable to find and execute script, despite being in the correct directory [duplicate]

I have a basic start script for an application that I am trying to run. However, every time I execute it: ./start.sh It fails with this error: -ksh: ./start.sh: not found [No such file or ...
0
votes
2answers
1k views

Errno 5 Input/output error when running yum check-update

I tried to update a server over SSH, but when I ran yum check-update I got an error: [error 5] Input/output error I think this means the RPM libraries may be damaged or corrupt, but I'm not sure ...