Linux - Revision history

Kai: Adding note on ssh remote connections with Visual Studio Code

2025-04-10T10:26:49Z

Adding note on ssh remote connections with Visual Studio Code

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-= C++ programming notes =
+= Programming notes =
-== Platform detection ==
+== Remote Programming over SSH with Visual Studio Code ==
 To detect whether code is compiled for the Linux platform you can check if ''__linux__'' is defined.
 <pre class="code">

Kai: /* SSH Logins Without Typing The Password */

2023-01-17T11:04:32Z

SSH Logins Without Typing The Password

← Older revision		Revision as of 2023-01-17T11:04:32
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	= SSH Logins Without Typing The Password =		= SSH Logins Without Typing The Password =
	If you connect to a remote ~~computer~~ via ''ssh'' or copy files via ''scp'' frequently, you should consider using ''ssh-agent''~~, which saves you from~~ typing your ~~login~~ password ~~each time~~.		If you connect to a remote machine via ''ssh'' or copy files via ''scp'' frequently, you should consider transferring your public key to the remote machine and using ''ssh-agent'' locally in order to log in without typing your password.
	~~<br />~~
	<br />		<br />
			== Generating An SSH Key ==
	First, you create an RSA public/private key pair that identifies your local machine. You may already have created such a key in your SSH keychain. It is good security practice, however, to use a separate key for each device you want to connect to. Let us assume you want to connect to a [[Raspberry Pi]]. The command to create a new SSH key would be		First, you create an RSA public/private key pair that identifies your local machine. You may already have created such a key in your SSH keychain. It is good security practice, however, to use a separate key for each device you want to connect to. Let us assume you want to connect to a [[Raspberry Pi]]. The command to create a new SSH key would be
	<pre class="terminal">		<pre class="terminal">
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	where '-b 2048' specifies the key length in bits. You will be prompted to enter the path and name of the file in which the key will be saved. Choose a name that makes it clear that it was created for connecting to the Raspberry Pi. Next, you will be prompted for a password. Just press the Enter key for no password.		where '-b 2048' specifies the key length in bits. You will be prompted to enter the path and name of the file in which the key will be saved. Choose a name that makes it clear that it was created for connecting to the Raspberry Pi. Next, you will be prompted for a password. Just press the Enter key for no password.
	<br />		<br />
	~~<br />~~		== Transferring Your Public SSH Key ==
	Now that the SSH key is created, you need to ~~copy~~ the generated key ~~(''~~'public~~''')~~ into the ~~folder~~ ''~~/home/pi~~/.ssh/'' on the ~~Raspberry Pi:~~		Now that the SSH key is created, you need to transfer the generated public(!) key to the remote machine. If the remote machine will ever only be accessed with a single SSH identity, you can simply copy the user's public key into the ''~/.ssh'' folder on the remove machine.
	<pre class="terminal">		<pre class="terminal">
	scp ~/.ssh/~~for-raspberry-pi_rsa~~.pub pi@192.168.1.10:/home/pi/.ssh/authorized_keys		scp ~/.ssh/id_rsa.pub pi@192.168.1.10:/home/pi/.ssh/authorized_keys
	</pre>		</pre>
	~~The~~ copied file is renamed to '''authorized_keys''', which is the expected file name for the SSH server to look up the public keys of trusted clients.		where the copied file is renamed to '''authorized_keys''', which is the expected file name for the SSH server to look up the public keys of trusted clients.
			<br />
	<br />		<br />
	~~If ''authorized_keys'' is to hold multiple keys~~, you should use '''ssh-copy-id''' ~~instead of~~ ''~~scp~~'':		Generally, however, you should use '''ssh-copy-id''' to transfer the SSH identity. This tool appends the SSH identity to the remote ''~/.ssh/authorized_keys'' instead of overwriting it.
	<pre class="terminal">		<pre class="terminal">
	ssh-copy-id -i ~/.ssh/~~for-raspberry-pi_rsa~~.pub pi@192.168.1.10		ssh-copy-id -i ~/.ssh/id_rsa.pub pi@192.168.1.10
	</pre>		</pre>
	<br />		<br />
	~~Now use~~ ''ssh-agent'' on your local machine to start a special shell session that uses the new SSH key to automatically authenticate any SSH connection from your machine to the Raspberry Pi:		== Launching ssh-agent ==
			Use ''ssh-agent'' on your local machine to start a special shell session that uses the new SSH key to automatically authenticate any SSH connection from your machine to the Raspberry Pi:
	<pre class="terminal">		<pre class="terminal">
	eval "$(ssh-agent -s)" # starting a new shell session		eval "$(ssh-agent -s)" # starting a new shell session
	ssh-add ~/.ssh/for-raspberry-pi_rsa		ssh-add ~/.ssh/for-raspberry-pi_rsa
	</pre>		</pre>
	Done! This was the last time you had to enter the password for user ~~''pi''~~.		<br />
			Done! This was the last time you had to enter the password for the remote user.
	<br />		<br />
	<br />		<br />
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	</pre>		</pre>
	<br />		<br />


	= Bluetooth =		= Bluetooth =

Kai: /* Device Tree Overlays */

2022-12-24T14:13:03Z

Device Tree Overlays

← Older revision		Revision as of 2022-12-24T14:13:03
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	dtc -@ -I dts -O dtb -o camera_overlay.dtbo camera_overlay.dts		dtc -@ -I dts -O dtb -o camera_overlay.dtbo camera_overlay.dts
	</pre>		</pre>
	~~=== dtoverlay ===~~		<br />
	~~'''dtoverlay''' is used to dynamically load device tree overlays, or unload previously loaded overlays.~~
	~~<pre class="terminal">~~

	</~~pre~~>

	= Systemd =		= Systemd =

Kai: Adds initial content to device trees section.

2022-12-24T12:14:51Z

Adds initial content to device trees section.

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 = Device Trees =
 <br />
 = Systemd =

Kai: Adds empty section about device trees. Changes heading sizes.

2022-12-24T10:58:21Z

Adds empty section about device trees. Changes heading sizes.

Show changes

Kai: Adds section about Videl4Linux.

2022-12-09T13:33:34Z

Adds section about Videl4Linux.

← Older revision		Revision as of 2022-12-09T13:33:34
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	my_arch=`uname -i`		my_arch=`uname -i`
	g++ -o ble-peripheral main.cpp -L/usr/lib/${my_arch}-linux-gnu -lsdbus-c++		g++ -o ble-peripheral main.cpp -L/usr/lib/${my_arch}-linux-gnu -lsdbus-c++
			</pre>
			<br />

			== Video4Linux ==
			Video4Linux is the video pipeline control system in Linux. Start by installing the required packages. On a Debian distribution, type
			<pre class="terminal">
			sudo apt install libv4l-0 v4l-utils v4l-conf libv4lconvert0

			v4l2-ctl --list-devices
	</pre>		</pre>
	<br />		<br />

Kai: Adds section about using ssh-agent.

2022-12-09T13:17:55Z

Adds section about using ssh-agent.

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 sudo apt install ltrace
 </pre>
 <br />
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 </pre>
 <br />
 == Message of the Day (MOTD) ==
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 </pre>
 <br />
 <br />

Kai: Adds section about customizing the Message of the Day (MOTD).

2022-12-09T13:05:15Z

Adds section about customizing the Message of the Day (MOTD).

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 <br />
 <br />
 == Bluetooth ==

Kai: Adds section about Bluetooth wireless communication.

2022-12-09T12:40:40Z

Adds section about Bluetooth wireless communication.

@@ Line 374: / Line 374: @@
 </pre>
 <br />
 <br />

Kai: Adds subsection on controlling systemd services.

2022-12-09T12:36:04Z

Adds subsection on controlling systemd services.

@@ Line 45: / Line 45: @@
 sudo systemctl list-dependencies
 </pre>
 <br />