The Official Instructions for a Raspberry pi 4 do not allow for working sound from the headphone jack, unless you use the aarch64 Installation.

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tar Create Combine many files and directories into a single t-archive file. 1tar cf "$ARCHIVE".tar $DIR You can remember this with the mnemonic 'Create File'. Unfortunately, this stores the full file path, so making a tar archive of /etc/nginx/ will store etc/nginx (without the leading /). It's often better to tell tar …

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Install with: 1sudo apt install at Enable the daemon service with: 1sudo systemctl enable --now atd Then jobs can be specified with absolute time, such as: 1at 16:20 1at noon 1at midnight 1at teatime Type in your command, e.g.: 1touch /tmp/$FILE.txt The jobs can also be specified relative to the current time: 1at now …

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Automatic Login Edit /etc/systemd/system/getty@tty1.service.d/override.conf by typing: 1sudo systemctl edit getty@tty1 The put in the following, changing [ USER ] to your username. 1[Service] 2ExecStart= 3ExecStart=-/usr/bin/agetty --autologin [ USER ] -s %I 115200,38400,9600 vt102 Automatically Start X In .bashrc. 1 …

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Basics See a file's contents: Return full contents of a string: 1awk '{ print }' file Print the first and second column: 1awk '{print$1$2}' Return every line with the word 'the' (like grep): 1awk '/the/{print}' file Print everything containing a lowercase letter: 1awk '/[a-z]/{print}' file Same with numbers [0-9], or …

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Base 16 numbers often use 0x at the start, so '10' just means '10', but 0x10 means '10 in base 16' which means '16'. For small numbers, use printf. 1printf "%x" $NUMBER For any number, use bc. 1fortune | md5sum | cut -d' ' -f1 | tr [:lower:] [:upper:] | bc Inputting base 16 uses ibase=16. Outputting base 10 uses …

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Games are a great way to learn bash. mapscii.me is an interactive terminal map. Install telnet. telnet mapscii.me Over the Wire teaches bash with small challenging you can do over ssh.

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Track Live Changes See changes in a file as it changes: tail -f somefile See changes in a directory, as it changes: watch -d ls directory Or use the -g flag to exit once the output changes. This command will look at whether you're connected to the internet, and turn into a rainbow once the connection hits. watch -g …

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Pulse If you have pulse, use pulse. Check with which pulseaudio. No output means you need to use alsa (below). Volume Control 1pactl set sink @DEFAULT_SINK@ +5% Find working outputs: 1aplay -l #Sound Settings Surround.5 seems best. Find what Sound settings exist amixer scontrols Change a Sound setting 1amixer set …

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You need about a dozen commands to move around Linux. After that, you look up the rest as you go. Don't worry about understanding any of it, just type it in and the habit forms pretty quickly. You start in a dark room. You want to know where you are by printing out your working 'directory' (i.e. 'location'): 1pwd Have …

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