os_cp:intro
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os_cp:intro [2025/03/06 13:54] (current) jkonczak [Listing directory contents] |
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| POSIX - a standard (published by IEEE and The Open Group) for operating system interface and environment, predominantly built to unify Unix-like systems | POSIX - a standard (published by IEEE and The Open Group) for operating system interface and environment, predominantly built to unify Unix-like systems | ||
| - | <html><small></html> | + | <small> |
| - | GNU/Linux | + | Linux, GNU/Linux, Linux distribution… |
| * [[https://www.gnu.org/gnu/gnu.html|GNU]] is a collection of free software that altogether forms an operating system supplied with a broad choice of user applications [[https://www.gnu.org/manual/blurbs.html]] | * [[https://www.gnu.org/gnu/gnu.html|GNU]] is a collection of free software that altogether forms an operating system supplied with a broad choice of user applications [[https://www.gnu.org/manual/blurbs.html]] | ||
| * the kernel of GNU, [[https://www.gnu.org/software/hurd/|Hurd]], has never been fit enough for the task | * the kernel of GNU, [[https://www.gnu.org/software/hurd/|Hurd]], has never been fit enough for the task | ||
| * therefore GNU software is usually run on top of Linux kernel | * therefore GNU software is usually run on top of Linux kernel | ||
| - | * most Linux distributions, apart form GNU software, has also a multitude of other software (not necessarely free or open source) | + | * most Linux distributions, apart form GNU software, has also a multitude of other software (not necessarily free or open source) |
| + | * some Linux distributions base on free and/or open source software that is neither GNU software nor uses GNU licenses | ||
| - | <html></small></html> | + | </small> |
| ==== Shell and vital utilities ==== | ==== Shell and vital utilities ==== | ||
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| * Apple operating systems (e.g. MacOS) ship with modified BSD tools [[https://opensource.apple.com/releases/|[1]]] [[https://github.com/apple-oss-distributions/file_cmds|[2]]] [[https://github.com/apple-oss-distributions/text_cmds|[3]]] | * Apple operating systems (e.g. MacOS) ship with modified BSD tools [[https://opensource.apple.com/releases/|[1]]] [[https://github.com/apple-oss-distributions/file_cmds|[2]]] [[https://github.com/apple-oss-distributions/text_cmds|[3]]] | ||
| * Embedded / resource restrained systems often use [[https://www.busybox.net/downloads/BusyBox.html|BusyBox]] | * Embedded / resource restrained systems often use [[https://www.busybox.net/downloads/BusyBox.html|BusyBox]] | ||
| - | * Android uses [[https://www.landley.net/toybox/|toybox]] [[https://cs.android.com/android/platform/superproject/main/+/main:external/toybox/toys/posix/|[4]]] | + | * Android uses [[https://www.landley.net/toybox/|toybox]] [[https://cs.android.com/android/platform/superproject/main/+/main:external/toybox/toys/posix/|[4]]] |
| * For more, see [[https://wiki.archlinux.org/title/core_utilities]] | * For more, see [[https://wiki.archlinux.org/title/core_utilities]] | ||
| <html></small></html> | <html></small></html> | ||
| - | POSIX standarizes both the [[https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html|shell]] | + | POSIX standarizes both the [[https://pubs.opengroup.org/onlinepubs/9799919799/utilities/V3_chap02.html|shell]] |
| - | and its vital [[https://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html|utilities]]. | + | and its vital [[https://pubs.opengroup.org/onlinepubs/9799919799/utilities/contents.html|utilities]]. |
| ==== Accessing the shell ==== | ==== Accessing the shell ==== | ||
| Line 78: | Line 79: | ||
| * terminals bundled with some Linux desktop environment: [[https://docs.xfce.org/apps/terminal/start|xfce4-terminal]], [[https://en.wikipedia.org/wiki/GNOME_Terminal|GNOME Terminal]], [[https://konsole.kde.org/|konsole]] | * terminals bundled with some Linux desktop environment: [[https://docs.xfce.org/apps/terminal/start|xfce4-terminal]], [[https://en.wikipedia.org/wiki/GNOME_Terminal|GNOME Terminal]], [[https://konsole.kde.org/|konsole]] | ||
| * default MacOS [[https://en.wikipedia.org/wiki/Terminal_(macOS)|Terminal]] | * default MacOS [[https://en.wikipedia.org/wiki/Terminal_(macOS)|Terminal]] | ||
| - | * drop-down terminals: [[https://apps.kde.org/yakuake/|yakuake]] / [[http://guake-project.org/|guake]](([[https://web.archive.org/web/20230709030453/http://guake-project.org/|Project homepage archived by archive.org]], [[https://github.com/Guake/guake/|github]])) / [[https://github.com/lanoxx/tilda|tilda]] | + | * drop-down terminals: [[https://apps.kde.org/yakuake/|yakuake]] / [[https://guake.github.io/|guake]] / [[https://github.com/lanoxx/tilda|tilda]] |
| <html></small></html> | <html></small></html> | ||
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| It is vital for security to confirm the authenticity of the server – the client | It is vital for security to confirm the authenticity of the server – the client | ||
| must verify that it does not contact a rogue server that can learn the password | must verify that it does not contact a rogue server that can learn the password | ||
| - | ([[https://docs.ssh-mitm.at/user_guide/authentication.html#id2|ready-to-go tool]]) | + | ([[https://docs.ssh-mitm.at/user_guide/authentication.html#id2|ready-to-go tool]]) |
| and/or hijacks the session. | and/or hijacks the session. | ||
| \\ | \\ | ||
| Line 120: | Line 121: | ||
| Hence, upon the first connection to a new server the SSH client program requests | Hence, upon the first connection to a new server the SSH client program requests | ||
| the user to verify the authenticity of the public key and stores the key (in | the user to verify the authenticity of the public key and stores the key (in | ||
| - | OpenSSH in ''~/.ssh/known_hosts'') to verify it automatically upon subsequent | + | OpenSSH in ''~/.ssh/known_hosts'') to verify it automatically upon subsequent |
| connections. | connections. | ||
| Line 127: | Line 128: | ||
| ~~Exercise.#~~ Run a terminal emulator. Execute command ''date'' and ''echo $SHELL'' within. | ~~Exercise.#~~ Run a terminal emulator. Execute command ''date'' and ''echo $SHELL'' within. | ||
| - | ~~Exercise.#~~ Execute command ''sleep 1h'' and interrupt it by pressing //Ctrl + c//. | + | ~~Exercise.#~~ Execute command ''sleep 1h'' and interrupt it by pressing //Ctrl + c//. |
| ~~Exercise.#~~ Switch to second virtual console and log in. Execute ''pwgen''. Return to graphical console. | ~~Exercise.#~~ Switch to second virtual console and log in. Execute ''pwgen''. Return to graphical console. | ||
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| The command **''ls [//dir//]''** lists file in directory ''dir''. When run with no arguments, it lists the current working directory. | The command **''ls [//dir//]''** lists file in directory ''dir''. When run with no arguments, it lists the current working directory. | ||
| \\ | \\ | ||
| - | By default ''ls'' does not list hidden files. The **''-a''** and ''--all'' switch changes this behaviour. | + | By default ''ls'' does not list hidden files. The **''-a''** switch changes this behaviour. |
| \\ | \\ | ||
| - | Switch **''-l''** / ''--list'' prints list of files with details such as file owner, size, modification date, etc. | + | Switch **''-l''** prints list of files with details such as file owner, size, modification date, etc. |
| ~~Exercise.#~~ List files in ''/usr/share/zoneinfo/'' and ''../../../../../bin''. | ~~Exercise.#~~ List files in ''/usr/share/zoneinfo/'' and ''../../../../../bin''. | ||
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| \\ | \\ | ||
| For instance, //lines beginning with a word followed by an equals sign// might | For instance, //lines beginning with a word followed by an equals sign// might | ||
| - | be written as a regular expression ''^\w+=''. | + | be written as a regular expression ''^\w+=''. |
| There are countless syntaxes and implementations of such patterns/expressions. | There are countless syntaxes and implementations of such patterns/expressions. | ||
| In the shell, [[https://en.wikipedia.org/wiki/Wildcard_character|wildcards]] | In the shell, [[https://en.wikipedia.org/wiki/Wildcard_character|wildcards]] | ||
| - | and [[https://en.wikipedia.org/wiki/Regular_expression|regular expressions]] | + | and [[https://en.wikipedia.org/wiki/Regular_expression|regular expressions]] |
| are commonplace. | are commonplace. | ||
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| \\ | \\ | ||
| The shell uses syntax summarized e.g., in | The shell uses syntax summarized e.g., in | ||
| - | ''[[https://man7.org/linux/man-pages/man7/glob.7.html|man 7 glob]]'' and | + | ''[[https://man7.org/linux/man-pages/man7/glob.7.html|man 7 glob]]'' and |
| - | ''[[https://man7.org/linux/man-pages/man7/regex.7.html|man 7 regex]]'' | + | ''[[https://man7.org/linux/man-pages/man7/regex.7.html|man 7 regex]]'' |
| </small> | </small> | ||
os_cp/intro.1708432177.txt.gz · Last modified: 2024/02/20 13:29 by jkonczak
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