LVM

Default application

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# determine a file's MIME type
$ xdg-mime query filetype foo.pdf
application/pdf
# choose the default application for this file
$ xdg-mime query default application/pdf
# open a file with its default application
$ xdg-mime default qpdfview.desktop application/pdf

7z

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sudo apt install p7zip-full p7zip-rar
7z e file.7z
7z a OutputFile files_to_compress

tar

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tar jcvf - logs/ | split -b 1m - logs.tar.bz2
cat logs.tar.bz2.a* | tar xj

Ffmpeg

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ffmpeg -i in.mp4 -ss 01:01:01 -to 02:02:02 -c copy -bsf:v h264_mp4toannexb -f mpegts out.ts
ffmpeg -i "concat:1.ts|2.ts" -c copy -bsf:a aac_adtstoasc output.mp4

Connect debug serial port

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sudo gpasswd -a USER dialout
picocom --baud 115200 --flow n --parity n --databits 8 --stop 1 /dev/ttyUSB0

Change to random password

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echo "root:$(pwgen 32 1)" | chpasswd

Create new user

  1. useradd -m -s /bin/bash deploy
  2. sudo without password echo "deploy ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/101-deploy

Check block device

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sudo blkid
lsblk

Netplan

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

Systemd

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systemctl daemon-reload # Reload systemd manager configuration, scanning for new or changed units
journalctl -p debug -f -u UNIT # tail log
  • Common service names: systemd-networkd, systemd-resolved, systemd-timesyncd, cron.target, sshd

Python3

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python3 -m pip install --upgrade pip
python3 -m pip install wheel
python3 -m pip install pygame==2.0.0.dev8