Книги для Системного Администратора

find /path/to/logs -type f -name "*.log" -mtime +7 -exec rm {} \;

find /path/to/files -type f -name "*.txt" -exec gzip {} \;

grep -r "error" /var/log

grep -i -n "failed login" /var/log/auth.log

   v=spf1 include:_spf.google.com ~all
   

   v=DKIM1; k=rsa; p=MIIBIjANBgkqh...
   

   v=DMARC1; p=quarantine; rua=mailto:[email protected]; pct=100
   

pvcreate /dev/sdX

vgcreate my_vg /dev/sdX

lvcreate -L 10G -n my_lv my_vg

pvdisplay  # Физические тома
vgdisplay  # Группы томов
lvdisplay  # Логические тома

pvs  # PV
vgs  # VG
lvs  # LV

lvextend -L +5G /dev/my_vg/my_lv
resize2fs /dev/my_vg/my_lv  # Для ext4
xfs_growfs /dev/my_vg/my_lv  # Для XFS

lvremove /dev/my_vg/my_lv

vgremove my_vg

pvremove /dev/sdX

vgextend my_vg /dev/sdY

umount /dev/my_vg/my_lv
e2fsck -f /dev/my_vg/my_lv
resize2fs /dev/my_vg/my_lv 10G
lvreduce -L 10G /dev/my_vg/my_lv
mount /dev/my_vg/my_lv /mnt

lvcreate -L 1G -s -n my_snapshot /dev/my_vg/my_lv

lsblk  # Просмотр разделов
df -h  # Проверка занятого места
blkid  # Информация о файловых системах

wall "... текст сообщения ..."

... текст сообщения ...

pkill -9 -u `who | awk '{print $1}'| grep -v root|head -1

echo "какой-то текст" | write user

echo "какой-то текст" > /dev/pts/1   

df -h

du -sh /путь/к/директории

du -ah /путь | sort -rh | head -n 10

find / -type f -size +1G 2>/dev/null

find /var/log -type f -name "*.log" -mtime +30 -exec rm -f {} \;

sudo apt-get clean
sudo dnf clean all

sudo rm -rf /tmp/* /var/tmp/*

sudo apt-get autoremove --purge

0 3 * * 7 find /var/log -type f -name "*.log" -mtime +30 -exec rm -f {} \;

mv /большая/папка /mnt/новый_диск
ln -s /mnt/новый_диск /большая/папка

gzip /var/log/*.log

fdupes -r /путь

sudo apt install ncdu && ncdu /

iotop

sudo apt install fslint

df -h

iotop

inotifywait -m /путь

   * * * * * command_to_execute
   | | | | |
   | | | | +---- День недели (0 - вс, 6 - сб)
   | | | +------ Месяц (1 - 12)
   | | +-------- День месяца (1 - 31)
   | +---------- Час (0 - 23)
   +------------ Минуты (0 - 59)
   

     0 3 * * * /path/to/script.sh
     

     */15 * * * * /path/to/script.sh
     

   crontab -e
   

   [Unit]
   Description=My Task Service

   [Service]
   ExecStart=/path/to/script.sh
   

   [Unit]
   Description=Run My Task Every Day

   [Timer]
   OnCalendar=daily
   Persistent=true

   [Install]
   WantedBy=timers.target
   

     systemctl enable mytask.timer
     

     systemctl start mytask.timer
     

     systemctl list-timers
     

   sudo netplan apply
   

   sudo netplan try
   

   sudo netplan generate
   

   sudo netplan --debug apply
   

network:
  version: 2
  ethernets:
    enp0s3:
      dhcp4: true

network:
  version: 2
  ethernets:
    enp0s3:
      dhcp4: false
      addresses:
        - 192.168.1.100/24
      gateway4: 192.168.1.1
      nameservers:
        addresses:
          - 8.8.8.8
          - 1.1.1.1

network:
  version: 2
  ethernets:
    enp0s3:
      dhcp4: false
  vlans:
    vlan10:
      id: 10
      link: enp0s3
      addresses:
        - 192.168.10.100/24

network:
  version: 2
  wifis:
    wlan0:
      dhcp4: true
      access-points:
        "SSID":
          password: "your_password"

network:
  version: 2
  ethernets:
    enp0s3:
      dhcp4: false
  bridges:
    br0:
      interfaces:
        - enp0s3
      addresses:
        - 192.168.1.100/24
      gateway4: 192.168.1.1
      nameservers:
        addresses:
          - 8.8.8.8

$IP = "10.10.10.10"
$MaskBits = 24 # This means subnet mask = 255.255.255.0
$Gateway = "10.10.10.1"
$Dns = "10.10.10.100"
$IPType = "IPv4"
# Retrieve the network adapter that you want to configure
$adapter = Get-NetAdapter | ? {$_.Status -eq "up"}
# Remove any existing IP, gateway from our ipv4 adapter
If (($adapter | Get-NetIPConfiguration).IPv4Address.IPAddress) {
 $adapter | Remove-NetIPAddress -AddressFamily $IPType -Confirm:$false
}
If (($adapter | Get-NetIPConfiguration).Ipv4DefaultGateway) {
 $adapter | Remove-NetRoute -AddressFamily $IPType -Confirm:$false
}
 # Configure the IP address and default gateway
$adapter | New-NetIPAddress `
 -AddressFamily $IPType `
 -IPAddress $IP `
 -PrefixLength $MaskBits `
 -DefaultGateway $Gateway
# Configure the DNS client server IP addresses
$adapter | Set-DnsClientServerAddress -ServerAddresses $DNS

$IPType = "IPv4"
$adapter = Get-NetAdapter | ? {$_.Status -eq "up"}
$interface = $adapter | Get-NetIPInterface -AddressFamily $IPType
If ($interface.Dhcp -eq "Disabled") {
 # Remove existing gateway
 If (($interface | Get-NetIPConfiguration).Ipv4DefaultGateway) {
 $interface | Remove-NetRoute -Confirm:$false
 }
 # Enable DHCP
 $interface | Set-NetIPInterface -DHCP Enabled
 # Configure the DNS Servers automatically
 $interface | Set-DnsClientServerAddress -ResetServerAddresses
}

   grep "строка" имя_файла
   

   grep "строка" файл1 файл2
   

   grep -r "строка" /путь/к/каталогу
   

   grep -i "строка" имя_файла
   

   grep -n "строка" имя_файла
   

   grep -v "строка" имя_файла
   

   grep --color "строка" имя_файла
   

   grep -c "строка" имя_файла
   

   grep -E "регулярное_выражение" имя_файла
   

   egrep "регулярное_выражение" имя_файла
   

   grep -A 3 -B 2 "строка" имя_файла
   

   grep -l "строка" *
   

   grep -L "строка" *
   

   grep "error" /var/log/syslog
   

   grep -Eo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' имя_файла
   

   grep "pattern" имя_файла > output.txt
   

     sudo apt-get install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils
     

     sudo yum install qemu-kvm libvirt virt-install bridge-utils
     

     egrep -c '(vmx|svm)' /proc/cpuinfo
     

   sudo virt-install --name vm_name --ram 1024 --vcpus 1 --disk path=/var/lib/libvirt/images/vm_name.img,size=10 --cdrom /path/to/iso
   

     virsh start vm_name
     

     virsh shutdown vm_name
     

     virsh list --all
     

   virsh dominfo vm_name
   

     # Создание моста
     sudo brctl addbr br0
     sudo brctl addif br0 eth0
     sudo ifconfig br0 up
     

   ip addr
   

   ip addr show eth0
   

   ip link set eth0 up
   

   ip link set eth0 down
   

   ip addr add 192.168.1.10/24 dev eth0
   

   ip addr del 192.168.1.10/24 dev eth0
   

   ip route
   

   ip route add 192.168.2.0/24 via 192.168.1.1
   

   ip route del 192.168.2.0/24
   

    ip -s link
    

    ip link set dev eth0 address 00:11:22:33:44:55
    

    ip link show
    

    ip -s route
    

man ip

   ifconfig
   

   ifconfig eth0
   

   ifconfig eth0 192.168.1.10
   

   ifconfig eth0 netmask 255.255.255.0
   

   ifconfig eth0 up
   

   ifconfig eth0 down
   

   ifconfig eth0 hw ether 00:11:22:33:44:55
   

   ifconfig eth0 broadcast 192.168.1.255
   

   ifconfig eth0 stats
   

  ifconfig -a
  

  ifconfig eth0:0 192.168.1.20
  

  ifconfig route
  

man ifconfig

   rm ./-rf
   

   rm -- -rf
   

   nft list ruleset               # Показать все правила
   nft add table ip filter        # Создать таблицу filter для IPv4
   nft add chain ip filter input  # Создать цепочку input в таблице filter
   

     nft add rule ip filter input ip saddr 127.0.0.1 accept
     

     nft add rule ip filter input tcp dport 80 drop
     

     nft add rule ip filter output accept
     

   nft delete rule ip filter input handle <номер>  # Удалить правило по handle
   nft delete chain ip filter input               # Удалить цепочку input
   nft delete table ip filter                     # Удалить таблицу filter
   

   nft list ruleset > /etc/nftables.conf          # Сохранить правила
   nft -f /etc/nftables.conf                      # Загрузить правила из файла
   

   nft add rule ip filter input log prefix "IN: " level debug
   

   nft add rule ip filter input limit rate 5/second accept
   

   nft add set ip filter blacklist { type ipv4_addr; }
   nft add rule ip filter input ip saddr @blacklist drop
   nft add element ip filter blacklist { 192.168.1.1, 10.0.0.0/8 }
   

   nft add rule ip nat prerouting tcp dport 80 redirect to 8080
   

#!/bin/bash
used=`df -hl / | awk {'print $4'} | grep "%"`
used=${used/\%/}
if [ $used -gt 90 ];
then
echo "Attention! Available space less than 10%. Used space = $used"% | mail -s "DISK ALERT" <a href="mailto:[email protected]">[email protected]</a>
fi

?
if ! [ -f /path/to/file ]; then
echo 'No file'
fi

if ! [ -d /path/directory/ ]; then
echo 'No directory'
fi

grep "username:" /etc/passwd >/dev/null
if [ $? -ne 0 ]; then
echo 'No username found'
fi

#!/bin/bash
#=====================================
# скрипт изменения кодировки файлов.
#=====================================
# суть для одного файла: iconv -f Исходная_кодировка -t В_какую_кодировку > выходной_файл
# CONFIG:
TYPES="*.txt"; # на случай поиска по расширению. напр. "*.log"
FROM='cp1251'; # из какой кодировки.
TO='utf8'; # в какую кодировку.
FILEPREFIX='.utf8'; # к названию перекодированного файла добавится.
 
# START:
if [ -z $1 ]
then
        echo "Encoding all $TYPES in directory From $FROM To $TO";
        echo "use $0 /Path_to_recoding_directory/"; echo;
        exit 1;
else
        echo "Encoding all $TYPES in directory $1 From $FROM To $TO";
        echo;
        find $1 -name "$TYPES" -type f -print0|while read -d '' SOURCE; do
                echo "========== SOURCE: $SOURCE FROM: $FROM TO: $TO ==========";
                cat "$SOURCE"|iconv -f $FROM -t $TO > "$SOURCE$FILEPREFIX";
                wait;
        done;
        exit 0;
fi
# end

#!/bin/sh
 
FILE_NAME="path_of_file"
 
HOST='IP Addr. of ftp server'
 
USER='user_name'
 
PASSWD='user_passwd'
 
ftp -nv <<EOF
open $HOST
user $USER $PASSWD
cd db_backups/PUNE/
put $FILE_NAME
 
EOF

./script.sh arg1 arg2 arg3

   for arg in $@; do
       echo $arg
   done
   

   arg1
   arg2
   arg3
   

   for arg in "$@"; do
       echo $arg
   done
   

   sudo apt update
   sudo apt install nvme-cli
   

   sudo nvme smart-log /dev/nvme0
   

sudo smartctl -a /dev/nvme0