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144 lines
3.8 KiB
144 lines
3.8 KiB
= An Introduction to Linux !
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Apostolos rootApostolos@swarmlab.io
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// Metadata:
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:description: Intro and Install
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:keywords: Linux, apt
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:data-uri:
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:toc: right
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:toc-title: Table of contents
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:toclevels: 4
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:source-highlighter: highlight
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:no-header-footer:
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:nofooter:
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:last-update-label!:
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:icons: font
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:sectnums:
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== Absolute basics
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.Absolute basics
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[options="header,footer"]
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|=======================
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|Command| Meaning
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|ls| Displays a list of files in the current working directory.
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|cd directory| change directories
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|passwd |change the password for the current user
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|file filename| display file type of file with name filename
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|cat textfile| throws content of textfile on the screen
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|pwd| display present working directory
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|exit or logout| leave this session
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|man command| read man pages on command
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|=======================
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=== Key combinations
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.Key combinations
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[options="header,footer"]
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|=======================
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|Key or key combination| Function
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|Ctrl+C| End a running program and return the prompt
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|Ctrl+Z| Suspend a program
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|ArrowUp and ArrowDown| Browse history. Go to the line that you want to repeat, edit details if necessary, and press Enter to save time.
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|Tab| Command or filename completion; when multiple choices are possible, the system will either signal with an audio or visual bell, or, if too many choices are possible, ask you if you want to see them all.
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|Tab Tab| Shows file or command completion possibilities.
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|Shift+PageUp and Shift+PageDown| Browse terminal buffer (to see text that has "scrolled off" the screen).
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|=======================
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=== ls -l
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[source,bash]
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----
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# ls -al
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drwxrwxr-x 4 zeus zeus 4096 Οκτ 23 21:55 .
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drwxrwxr-x 9 zeus zeus 4096 Οκτ 15 14:28 ..
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drwxrwxr-x 8 zeus zeus 4096 Οκτ 23 21:55 .git
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drwxrwxr-x 4 zeus zeus 4096 Οκτ 14 20:24 install
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crw------- 1 root root 5, 1 Οκτ 23 21:22 console
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lrwxrwxrwx 1 root root 11 Οκτ 23 21:21 core -> /proc/kcore
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drwxr-xr-x 4 root root 100 Οκτ 23 21:22 cpu
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crw------- 1 root root 10, 59 Οκτ 23 21:21 cpu_dma_latency
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crw------- 1 root root 10, 203 Οκτ 23 21:21 cuse
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-rw-rw-r-- 1 zeus zeus 1517 Οκτ 23 21:55 INSTALL.md
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-rw-rw-r-- 1 zeus zeus 33883 Οκτ 15 14:28 LICENSE
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-rw-rw-r-- 1 zeus zeus 691 Οκτ 17 11:13 README.md
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----
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==== File types
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This table gives an overview of the characters determining the file type:
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NOTE: **d**rwxrwxr-x 4 zeus zeus 4096 Οκτ 14 20:24 install
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.File types in a long list
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[options="header,footer"]
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|=======================
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|Symbol| Meaning
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|-| Regular file
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|d| Directory
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|l| Link
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|c| Special file
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|s| Socket
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|p| Named pipe
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|b| Block device
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|=======================
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NOTE: -**rw-**rw-r-- 1 zeus zeus 1517 Οκτ 23 21:55 INSTALL.md
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==== Access rights
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.Access rights
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[options="header,footer"]
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|=======================
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|Code| Meaning
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|0 or -|The access right that is supposed to be on this place is not granted.
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|4 or r|read access is granted to the user category defined in this place
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|2 or w|write permission is granted to the user category defined in this place
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|1 or x|execute permission is granted to the user category defined in this place
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|=======================
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==== User group codes
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.User group codes
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[options="header,footer"]
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|=======================
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|Code| Meaning|
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|u| user permissions|-**rw-**rw-r--
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|g| group permissions|-rw-**rw-**r--
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|o| permissions for others|-rw-rw-**rw-**
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|=======================
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==== Exercises
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[source,bash]
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----
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touch example
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chmod 400 example
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ls -l example
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chmod 500 example
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ls -l example
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chmod 600 example
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ls -l example
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chmod 644 example
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ls -l example
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chmod 660 example
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ls -l example
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chmod 700 example
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ls -l example
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chmod 755 example
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ls -l example
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chmod 775 example
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ls -l example
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ls -l example
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chmod 777 example
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ls -l example
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----
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:hardbreaks:
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{empty} +
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{empty} +
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{empty}
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:!hardbreaks:
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