$ xdg-open http://$(ip --oneline route get 1.1.1.1 | awk '{print $3}')

$ sudo chgrp avengers file
-rw-rw-r-- 1 parallels avengers file

$ chgrp -h parallels file_ln
lrwxrwxrwx 1 root parallels file_ln -> ../file

$ chgrp -RH www-data /var/www
$ chgrp -RL www-data /var/www

rm: cannot remove 'file-or-directory': Device or resource busy

$ lsof +D Sources/App/
COMMAND   PID    USER   FD   NAME
server  22331 xoadmin  txt    Sources/App/server
client  22332 xoadmin  txt    Sources/App/client

$ fuser -k Sources/App/

$ rm -rf test
rm: cannot remove 'test/tmpfsdir': Device or resource busy

$ mount | grep test/tmpfsdir
none on /home/u/test/tmpfsdir type tmpfs (rw,relatime,inode64)

$ sudo umount test/tmpfsdir
$ rm -rf test

$ sudo apt install terminator

$ sudo apt install tilix

$ sudo apt install guake

$ sudo snap install todoist

$ sudo apt install timeshift

$ echo -e "computer\nmouse\nLAPTOP\ndata" > test.txt

$ cat test.txt
computer
mouse
LAPTOP
data

$ sort test.txt
computer
data
LAPTOP
mouse

$ sort -u /var/log/syslog 

$ ls -l | sort -k9
... 6 user user 4096 дек 6 14:29 Android
... 3 user user 4096 янв 14 22:18 Desktop
... 5 user user 12288 янв 15 14:59 Downloads
... 7 user user 4096 янв 13 11:42 Lightworks

$ ls -l | sort -nk2
... 5 user user 12288 янв 15 14:59 Downloads
... 6 user user 4096 дек 6 14:29 Android
... 7 user user 4096 июн 10 2015 Sources
... 8 user user 12288 янв 11 12:33 Pictures

$ rsync file1 file2 ... user@host:dest

$ rsync -a dir host:dest_dir

$ rsync -a --delete dir host:dest_dir

$ rsync -avh --del --progress dir1 dir2 dir3 backup

$ rsync -a --exclude=.git src host:

* * * * * команда
┬ ┬ ┬ ┬ ┬
│ │ │ │ └── День недели (0–7) — где 0 и 7 — это воскресенье
│ │ │ └──── Месяц (1–12)
│ │ └─────── День месяца (1–31)
│ └──────── Час (0–23)
└────────── Минута (0–59)

0 4 * * * /home/user/backup.sh

#!/bin/bash

LOG_DIR="/var/log/myapp"
DAYS_TO_KEEP=7

find "$LOG_DIR" -type f -name "*.log" -mtime +$DAYS_TO_KEEP -exec rm -f {} \;

chmod +x /home/user/noscripts/clear_logs.sh

0 0 * * 0 /home/user/noscripts/clear_logs.sh >> /var/log/clear_logs.log 2>&1

$ sudo du -sh ~/Downloads
96M /home/parallels/Downloads

$ sudo du -sSh ~/Downloads
92M /home/parallels/Downloads

$ sudo du -h ~/Downloads

$ sudo du -h --max-depth=1 /etc
16K /etc/lighttpd
8.0K /etc/python3
56K /etc/iproute2

$ sudo du -ah ~/Downloads
96M ...Downloads/code_1.99.3-1744760597_arm64.deb
4.0K ...Downloads/file-part_2
4.0K ...Downloads/file-part_1

$ sudo du -ah ~/Downloads | sort -rh
96M .../Downloads/code_1.99.3-1744760597_arm64.deb
96M .../Downloads
20K .../Downloads/test