The Linux console under control: shell tips and tricks

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The Linux console under control:  Man pages to command-line tools and commands are mostly extra-dry, but they are less deterrent in the PDF reader. SSH jumps with manage a roll backwards through the firewall.

linux console
linux console

Linux console: documentation

Read man pages as PDF
Command line commands and tools provide their own documentation under Linux. These manual pages, called “man pages”, provide a lot of text and application examples in the shell with the commandand / tool] to explain the use of a co man [commmmand and its options as well as parameters. For many pages, however, it is worthwhile to start the text in peace.

First, make sure that the distribution you are using also provides all the German-language manpages. Many systems leave this part of the documentation away, in order to save space. For Ubuntu / Mint, Debian install the package “manpages-de” and in Fedora “man-pages-de”, while for Open Suse the unofficial repository provides a suitable RPM package.

Comprehensive documentation in the terminal to read is tiring: The manual pages look much better in a PDF reader, black on white and with proportional fonts. To do this, you can create postscript files, which can then be opened with a reader such as Okular and Evince:

man -t bash >bash.ps
Linux console
Linux console

 

Linux console: documentation

Read man pages as PDF
Command line commands and tools provide their own documentation under Linux. These manual pages, called “man pages”, provide a lot of text and application examplesin the shell with the command man [command / tool] to explain the use of a command and its options as well as parameters. For many pages, however, it is worthwhile to start the text in peace.

First, make sure that the distribution you are using also provides all the German-language manpages. Many systems leave this part of the documentation away, in order to save space. For Ubuntu / Mint, Debian install the package “manpages-de” and in Fedora “man-pages-de”, while for Open Suse the unofficial repository provides a suitable RPM package.

Comprehensive documentation in the terminal to read is tiring: The manual pages look much better in a PDF reader, black on white and with proportional fonts. To do this, you can create postscript files, which can then be opened with a reader such as Okular and Evince:





documentation

Read man pages as PDF
Command line commands and tools provide their own documentation under Linux. These manual pages, called "man pages", provide a lot of text and application examples in the shell with the command man [command / tool] to explain the use of a command and its options as well as parameters. For many pages, however, it is worthwhile to start the text in peace.

 First, make sure that the distribution you are using also provides all the English -language manpages. Many systems leave this part of the documentation away, in order to save space. For Ubuntu / Mint, Debian install the package "manpages-us" and in Fedora "man-pages-us", while for Open Suse the unofficial repository provides a suitable RPM package.

Comprehensive documentation in the terminal to read is tiring. The manual pages look much better in a PDF reader, black on white and with proportional fonts. To do this, you can create postscript files, which can then be opened with a reader such as  Evince:

man -t bash >bash.ps

This command creates a postscript file called "bash.ps", for example the documentation for the shell "Bash". If it is to be a PDF instead, which is also easily readable with apps on tablets and smartphones.But the tool ps2pdf then makes the postscript file a PDF. It is part of the "ghostscript" package and pre-installed on most Linux distributions. With a tight

ps2pdf bash.ps

You will get a PDF file named "bash.pdf" in the same directory.

 

Ubuntu / Debian

Verifying Program Versions with APT

The package manager APT from Debian, which is also used with all other major DEB-based distributions and it is  one of the fastest and most comfortable software management tools. However APT is trimmed to speed with its commands apt-get and apt-cache and does not provide gigantic functionality. So there is no direct way to find out the version of a program that is in the package repository.

A trick APT reveals even without actual installation of a package whose version number. The parameter -s command simulates apt-get all actions and displays status, but it invites not download files. APT also shows which packages are installed in which version:

apt-get -s install [Paketname]

In the output of this command, the last two lines show the version number of the package. Since this is a simulation that does not change the system, you do not need root privileges or sudo .

Linux console
Linux console

 

Linux consol: configuration

Standard editor on the console
If you are dealing with different distributions, it quickly becomes clear that there are small but serious differences in the default programs on the console. Ubuntu and Debian used  nano as the default editor, whereas Fedora uses vim. Whenever another command line program calls an editor, such as the file manager Midnight Commander, or crontab, the default editor is used.

 Just vi and vim work on Linux beginners like dinosaurs from gray Unix-Vorzeit, which seem to be operated only with an extra finger on each hand. You can set the preferred default editor in the shell, but on each Linux system, if you have several installed. The simplest way is to define the user-specific environment variable $ EDITOR. The appropriate location for the definition is the configuration file ".bashrc" in the home directory, where you end up the line

export EDITOR=[/Pfad/zum/Editor]

enter.  how to  make the editor so entered to the shell standard. For nano, instead of the placeholder, enter / usr / bin / nano . Note that setting is always valid for the respective user. For example, to set the editor to root, enter the definition in the / root /. Bashrc ". A special case is sudo , because when executing programs, sudo first resets all environment variables.

sudo -E [Befehl/Programme]

With switch -E, sudo takes into account the user-specific environment variables.

linux console
linux console



SSH

Reverse SSH: Through the firewall
If Linux computers  are to be accessible in the local network via the Internet,SSH . And  port switching and port forwarding is necessary on the router. In the home network this is connected with some configuration effort, but no technical obstacle. Different in company networks or in public WLANs: A port forwarding is usually not possible there, since this a network administrator would have to set up.

 SSH (Secure Shell) into a protocol with client-server model. However, an SSH tunnel can also swap the role of client and server if the connection is previously initiated with an open return channel. The prerequisite is that both an SSH server runs on the Linux system (server) behind the firewall and also on the Linux PC (client), from which the former is accessed.

In addition, the client must be accessible from the outside, in the case of the domestic Linux PC, for example, via a normal port forwarding on the router. From the server, prepare the connection using this command:

ssh -R 1234:localhost:22 [Client]

Instead of the [Client] placeholder, specify the Internet IP address or the (dynamic) host name of the client that will be accessed later. Later on the client, you can use the already established SSH connection to connect back to the server from there:

ssh benutzername@localhost -p 1234

The required user name is the one on the server, and the port specified behind the -p parameter, here, for example, 1234, is the previously constructed back channel. If the connection is automatically terminated after a period of inactivity, SSH on the server needs a supplement in the configuration file "/ etc / ssh / sshd_config". Make sure that there are the two options

KeepAlive yes ServerAliveInterval 60

documentation

Read man pages as PDF
Command line commands and tools provide their own documentation under Linux. These manual pages, called "man pages", provide a lot of text and application examples in the shell with the command man [command / tool] to explain the use of a command and its options as well as parameters. For many pages, however, it is worthwhile to start the text in peace.

The Linux console under control:  First, make sure that the distribution you are using also provides all the German-language manpages. Many systems leave this part of the documentation away, in order to save space. For Ubuntu / Mint, Debian install the package "manpages-de" and in Fedora "man-pages-de", while for Open Suse the unofficial repository provides a suitable RPM package.

Comprehensive documentation in the terminal to read is tiring: The manual pages look much better in a PDF reader, black on white and with proportional fonts. To do this, you can create postscript files, which can then be opened with a reader such as Okular and Evince:

man -t bash >bash.ps
This command creates a postscript file called "bash.ps", for example, from the documentation for the shell "Bash". If it is to be a PDF instead, which is then also easily readable with apps on tablets and smartphones, then the tool ps2pdf then makes the postscript file a PDF. It is part of the "ghostscript" package and pre-installed on most Linux distributions. With a tight

ps2pdf bash.ps
You will get a PDF file named "bash.pdf" in the same directory.

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