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https://github.com/danog/learn-bash.git
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280 lines
6.9 KiB
Bash
280 lines
6.9 KiB
Bash
#!/bin/bash
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# Learn shell scripting script.
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# Created by Daniil Gentili.
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# This project is licensed under the GPLv3 license.
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# Thanks to The Linux Documentation Project and to everyone @ #openshells @freenode.
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# v1.1
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# First checks and functions.
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[ -f /bin/bash ] && bash="/bin/bash" || bash="$(which -a bash | tail -1)"
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echo "Video download script - Copyright (C) 2015 Daniil Gentili
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This program comes with ABSOLUTELY NO WARRANTY.
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This is free software, and you are welcome to redistribute it
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under certain conditions; see the LICENSE file."
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lineclear() { echo -en "\r\033[K"; }
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##### Tools detection and selection #####
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which smooth.sh &>/dev/null && smoothsh=y || smoothsh=n
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which ffmpeg &>/dev/null && ffmpeg=y || ffmpeg=n
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which wget &>/dev/null && {
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dl() {
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wget "$1" -O $2 $3
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}
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Q="-q"
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} || {
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dl() {
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curl "$1" -o $2 $3
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}
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Q="-s"
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}
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##### Self updating section #####
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ME=$(which $0 || echo $0)
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# !!!!!! Comment the following line before editing the script or all changes will be overwritten !!!!!! #
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echo -n "Self-updating script..." && dl http://daniilgentili.magix.net/learn.sh $ME $Q 2>/dev/null;chmod 755 $ME 2>/dev/null; lineclear
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clear
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press() {
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echo
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read -s -p "Press enter to continue: "; lineclear
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}
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r() {
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eval $current
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}
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s() {
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try=y
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exit
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}
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export -f s r
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learn_vi() {
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echo "Vi:
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For now I will just show you the basics of vi.
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To create/open a text file using vi you have to type the following command:
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vi name_of_the_file_you_want_to_create
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"
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press
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echo "Vi has 2 modes: command mode and text mode."
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press
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echo "In the text mode you can edit the text of
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any text file.
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In the command mode you can do things like
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copy, paste, undo,
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save and close
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the file you are editing.
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Since vi starts automatically
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in command mode,
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to switch to text mode
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you will have to type:
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i
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When you open/create a file."
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press
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echo "To save the file press ESC to switch to command mode and then type
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:wq
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To save the file and close vi or
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:w
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Only to save the file without exiting vi.
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"
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}
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learn_nano() {
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echo "Nano:
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For now I will just show you the basics of nano.
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To create and open a text file using nano you have to use
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the following command:
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nano name_of_the_file_you_want_to_create
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"
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press
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echo "Once you have written what you need, press CTRL+X and y to save and close the file or just CTRL+O only to save the file."
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}
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learn_2_lesson() {
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which vi &>/dev/null && vi="available" || vi="unavailable "
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which nano &>/dev/null && nano="available " || nano="unavailable"
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echo "First of all, the script creation.
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A script should have an sh extension (Note 1.) and no spaces in the filename.
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"
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press
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echo "Note 1: Actually any extension will do,
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but it's more recognizable this way.
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"
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press
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echo "Sublesson 1: She-bang and permissions.
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Every bash script can be executed
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simply by typing
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bash script.sh
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but to execute it with a simple
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./script.sh
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you then have to give execution permissions
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to the script with chmod:
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chmod +x script.sh
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means: add (+) execute (x) permissions to script.sh
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"
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press
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echo "and add a shebang at the beginning of the file.
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The she-bang is a character (#!) followed by the
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path of the bash binary,
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usually /bin/bash (in this case matches the
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current location of the binary,
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which is $bash).
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She-bang to use on this system:
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#!"$bash"
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"
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press
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echo "To create a file, we can use lots of editors,
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but I have provided
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instructions only for the commonest
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vi and nano: they should be available
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on most Linux systems.
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You can also use echo to create scripts.
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"
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press
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until [ "$editor" = "c" -o "$editor" = "3" ]; do
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clear
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echo -n "Sublesson 2: Editors.
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1. Nano (currently $nano on your system)
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2. Vi (currently $vi on your system)
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3. echo (currently available on your system)
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Your selection (number, c to continue): "
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read editor
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clear
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[ "$editor" = "1" ] && learn_nano
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[ "$editor" = "2" ] && learn_vi
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done
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echo "Sublesson 3: echo.
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Echo is one of the basic tools that are most commonly used in bash scripting: it prints out a message to the user. This very message is printed using echo.
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The usage of this command is very simple:
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echo Words to print.
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"
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press
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echo "If your phrase include newlines or special characters such as ', ;, :, &, !, and so on, you should enclose everything in quotes, like this:
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echo \"This is something,
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this is something else;
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and this is just a random set of special chars:
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&@%# :)\"
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"
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press
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echo "If your phrase also includes one of the following special characters, apart from being quoted they also have to be escaped using a backslash (\\):
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\\\"
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\\' if everything is enclosed in single quotes
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\\\$ if followed by a letter or number
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\\\`
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Example:
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echo This will print \\\"echo \\\` it works! \\\` \\\\ \\\"
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Will print:
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`echo This will print \\\"echo \\\` it works! \\\` \\\\ \\\"`
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"
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press
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echo 'If your phrase also includes a ! followed by a letter or number you should enclose the enclose the phrase in single quotes (\').'
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press
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echo "To create a file using echo the usage is also very simple:
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echo \"This and
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this text will go to a text file.\" > file.txt
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This will recreate the file.
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To append the text, insert two >> instead of 1 >
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Of course, you can easily change the extension from txt to sh to create a shell script (just don't forget the shebang).
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"
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press
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}
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learn_1() {
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echo "The shell is a command interpreter.
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More than just the insulating layer between
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the operating system kernel and the user, it's also
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a fairly powerful programming language.
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A shell program, called a script, is an easy-to-use
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tool for building applications by \"gluing together\"
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system calls, tools, utilities, and compiled binaries.
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Virtually the entire repertoire of UNIX commands,
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utilities, and tools is available
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for invocation by a shell script.
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If that were not enough, internal shell commands,
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such as testing and loop constructs,
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lend additional power and flexibility to scripts.
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Shell scripts are especially well suited for
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administrative system tasks and other routine
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repetitive tasks not requiring the bells and
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whistles of a full-blown tightly structured
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programming language."
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press
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}
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learn_2() {
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export current="learn_2_lesson"
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set +H
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learn_2_lesson
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until [ "$try" = "y" ]; do
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[ "$try" = "n" ] && echo "Try again (I know you can do it!)!"
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echo "
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Task:
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Create a script named first_script.sh that prints
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\"Hello World! :)\"
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(with the quotes) when you execute it. Use vi, nano or echo, type exit when you're done,
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r to repeat the lesson and s to skip the exercise."
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bash
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./first_script.sh 2>&1 | grep -q "^\"Hello World! :)\"$" && try=y && done=y && ./first_script.sh || try=n
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clear
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done
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[ "$done" = "y" ] && echo "Good Job!" || echo "Come back soon!"
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sleep 2
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}
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# Here we go!
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until [ "$n" = q ]; do
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echo -n "Welcome to the Learn shell scripting script!
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This script can be of great help
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if you want to learn shell scripting
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and how to use Linux in general.
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Created by Daniil Gentili.
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Thanks to the Linux Documentation Project
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for the introduction.
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To start, here are the lessons:
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1. Introduction.
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2. My first Hello World!
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Your selection (number, enter q to exit.): "
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try=
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read n
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clear
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eval learn_$n
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clear
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done
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