folder="~/Documents/photos"
prefix="img_"

cd "$folder"
i=1
for file in *; do
  ext="${file##*.}"
  mv "$file" "${prefix}${i}.${ext}"
  ((i++))
done

IMG1234.jpg, vacation.png, photo_01.jpeg

img_1.jpg, img_2.png, img_3.jpeg

mtr -T --port 443 vpn.example.com

mtr --interval 2 --timeout 10 --report 1.1.1.1

mtr --report --report-cycles 20 example.com

mtr --json 8.8.8.8 > result.json

mtr --aslookup --report example.com

mtr --mpls --report example.com

mtr -n --report 1.1.1.1

mtr -T --port 443 -n --json --report-cycles 15 1.1.1.1

pidof nginx

ls -l /proc/<PID>/fd | grep '(deleted)'

cp /proc/<PID>/fd/<fd_number> ./recovered.log

#!/bin/bash
set -x

src="/etc/hosts"
dst="/tmp/backup"

mkdir -p "$dst"
timestamp=$(date +%Y%m%d_%H%M%S)
cp "$src" "$dst/hosts_$timestamp"

echo "Backup created: $dst/hosts_$timestamp"

# ./backup.sh
+ src=/etc/hosts
+ dst=/tmp/backup
+ mkdir -p /tmp/backup
+ date +%Y%m%d_%H%M%S
+ timestamp=20251007_121330
+ cp /etc/hosts /tmp/backup/hosts_20251007_121330
+ echo 'Backup created: /tmp/backup/hosts_20251007_121330'
Backup created: /tmp/backup/hosts_20251007_121330

stream {
  upstream ssh {
  server 2.2.2.2:22022;
  }

  upstream web {
  server 2.2.2.2:443;
  }

  map $ssl_preread_protocol $upstream {
  "" ssh;
  "TLSv1.2" web;
  default 2.2.2.2:443;
  }

  server {
  listen 1.1.1.1:443;
  proxy_pass $upstream;
  ssl_preread on;
  }

}

http {

$ ssh root@1.1.1.1 -p443
Enter passphrase for key "/home/user/.ssh/id_rsa":

apt install linkchecker -y

linkchecker dir/

linkchecker --check-extern dir/

#!/bin/bash

# Request IP address or hostname from user
read -p "Specify IP address or hostname: " ip

# Send one ICMP request with timeout
if ping -c 1 -W 2 "$ip" &> /dev/null
then
    echo "[OK] Host $ip is responding"
else
    echo "[ERROR] Host $ip is not reachable"
fi

tcpdump -nn -i eth0 tcp port 443 -w /tmp/api443.pcap

tcpdump -nn -i eth0 -vvv -s 0 -A port 443 | grep -i "server_name"

tcpdump -nn -i eth0 udp port 53 or tcp port 53

tcpdump -nn -i eth0 -vv udp port 53 | grep -Ei "ServFail|NXDomain"

tcpdump -nn -i eth0 'tcp[tcpflags] & tcp-rst != 0'

tcpdump -nn -i eth0 'tcp[tcpflags] == tcp-syn'

tcpdump -nn -i eth0 host 10.10.22.15 -w /tmp/host.pcap

tcpdump -nn -i eth0 -s 0 -w trace-%F-%H%M%S.pcap -G 60 -W 5

cp report.txt /var/tmp/workdir/

cd /var/tmp/workdir/

cp report.txt /var/tmp/workdir/
cd <Alt+.>

cd /var/tmp/workdir/

cd !$
или
cd !.

mkdir cache_dir
rm -r !$

cp -r app_source /srv/apps/
cd !$

mv access.log /var/log/old/
vim !$

cp archive.tar.zst /mnt/storage/
cp !$ /srv/archives/

#!/bin/bash

# Отображаемое имя
NICKNAME="$1"
REMOTE_HOST="$2"
REMOTE_PORT="$3"

# Читаем ввод и добавляем подпись
(
  while read text; do
      echo "[$NICKNAME] $text"
  done
) | nc "$REMOTE_HOST" "$REMOTE_PORT"

chmod +x talker.sh

nc -lvp 5201

./talker.sh alpha 172.16.16.30 5201
Привет всем
Как связь?

nc -lvp 5201
Listening on 0.0.0.0 5201
Connection received on 172.16.16.31 46656
[alpha] Привет всем
[alpha] Как связь?