readme3

a37453aa · Siegel, Moritz · 88286ad1 · a37453aa
Commit a37453aa authored 2 years ago by Siegel, Moritz
--- a/readme.md
+++ b/readme.md
+---
+author: Markus Hickel, Moritz Siegel
+title: Linux Primer
+institute: VSC Research Center, TU Wien
+date: \today
+---
+
+
+### Timetable
+
+4 parts, each:
+
+- Lecture
+
+- Exercise
+
+- Demonstration
+
+- Break
+
+Lunchbreak from 12 to 1 pm.
+
+Questions? Always!
+
+
+<!---
+### Operating Systems
+
+Vote: What's your **operating systems**?
+
+- **Linux**
+
+- **macOS**
+
+- **Windows**
+-->
+
+
+### Why Linux?
+
+![](pictures/oses.svg){height=80% style="float: right;"}
+
+
+### What do you know about Linux?
+<!---
+By a show of hands:
+
+- Nothing
+
+- Terminal and command line
+
+- Files and directories
+
+- Permissions
+
+- Variables
+
+- Streams
+
+- Shell scripts
+-->
+
+
+### Terminal & Prompt
+
+Welcome to a **terminal** showing the default `bash prompt`.
+
+```{.bash .numberLines startFrom=""}
+myuser@mymachine: mylocation$
+trainee00@l31:~$
+trainee00@l41:~/mydir$
+```
+
+All the `typewriter` text, and all dark grey boxes mean **code**.
+
+Lines that start with a `"$"` means a **command in a terminal**.
+
+
+### Execution
+
+To execute a command or run a program, we **call** it.
+
+```{.bash .numberLines startFrom=""}
+$ whoami
+trainee00
+
+$ echo "hello world"
+hello world
+
+$ gcc myprogram.c
+```
+
+
+### History
+
+Type `history` for a log of all the commands you executed so far.
+
+```{.bash .numberLines startFrom=""}
+$ history
+whoami
+echo "hello world"
+gcc myprogram.c
+```
+
+For the last commands try `<Up-Arrow>`, or type `<CTRL>-R` to search
+for keyword.
+
+
+### Completion
+
+Type `<TAB>` when you enter a command to get **suggestions**.
+
+```{.bash .numberLines startFrom=""}
+$ e<TAB>
+e2freefrag             env                    eu-elflint
+e2fsck                 envsubst               eu-findtextrel
+e2image                eodc_commands.py       eu-make-debug-archive
+...
+```
+
+If there is only one possible match, it gets **completed**.
+
+```{.bash .numberLines startFrom=""}
+$ ec<TAB>
+echo
+```
+
+
+### Parameters
+
+Give your program more info: write parameters **following** the
+program name.
+
+1. Single-character with dash
+   ```{.bash .numberLines startFrom=""}
+   $ mycommand -a -b -c -d -e
+   $ ls -1alh
+   ```
+2. Multi-character with double dash
+   ```{.bash .numberLines startFrom=""}
+   $ mycommand --long-parameter
+   $ mycommand --flag-parameter=flag-value
+   $ ls --color=always
+   ```
+3. Strings
+   ```{.bash .numberLines startFrom=""}
+   $ mycommand mysource mydestination
+   $ cp myoldfile mynewfile
+   ```
+
+
+### Order
+
+Run **from** the source **to** the destination.
+  
+```{.bash .numberLines startFrom=""}
+$ mycommand mysource mydestination    # ok
+$ mycommand mydestination mysource    # probably wrong
+```
+Keep parameters and their arguments **together**.
+```{.bash .numberLines startFrom=""}
+$ mycommand -j 2 --color auto    # ok
+$ mycommand -j auto --color 2    # probably wrong
+```
+
+**Beware**, the spaces between program name and parameter are important.
+
+
+### Filesystem
+
+The filesystem has different **objects**.
+
+- Files
+   
+- Directories
+   
+- Links
+
+
+### Path
+
+Everything starts at the **root directory** `"/"`.
+
+```{.bash .numberLines startFrom=""}
+/
+/home/fs70824/trainee00
+/home/lv70824/trainee00/mydir
+```
+
+Objects can be referenced by their **absolute** or **relative** path.
+```{.bash .numberLines startFrom=""}
+/home/fs70824/trainee00/mydir/myfile
+mydir/myfile
+./myfile       # in this directory
+../myfile      # in the directory above
+```
+
+
+### Exercise 1
+
+- [ ] Start a **terminal** and login to **VSC**
+
+- [ ] What machine are you on?
+
+- [ ] Run these **commands** (without the `"$"`):
+
+    ```{.bash .numberLines startFrom=""}
+    $ man
+    $ man man
+    $ echo "hello world"
+    ```
+
+- [ ] Use **completion** to find out what this command could be:
+
+   ```{.bash .numberLines startFrom=""}
+    $ whoa
+    ```
+    
+- [ ] View your command **history**
+
+- [ ] **Search** for the `echo` command in your history
+
+
+### Look Around
+
+Type `ls` (list) to **look around**.
+
+```{.bash .numberLines startFrom=""}
+$ ls
+all_numbers_from_to.sh  delete_me_empty     delete_me_recursive
+```
+
+```{.bash .numberLines startFrom=""}
+$ ls -a
+.   delete_me_empty      empty_dir      one_string_two_words.sh
+..  delete_me_nonempty   fizz_buzz.c    .found_me_hiding.txt
+```
+
+
+### Move Around
+
+Type `pwd` (print working directory) to see your **current
+position**.
+
+```{.bash .numberLines startFrom=""}
+trainee00@l40:~$ pwd
+/home/fs70824/trainee00
+```
+
+Type `cd` (change directory) to **move around**.
+
+```{.bash .numberLines startFrom=""}
+$ cd /bin
+$ cd mydir
+$ cd ..              # go to parent directory
+$ cd ~               # go home
+$ cd -               # go to previous directory
+```
+
+
+### Create
+
+Type `mkdir` to **make** a new directory.
+
+```{.bash .numberLines startFrom=""}
+$ mkdir mynewdir
+```
+
+Type `touch` **create** an empty file.
+
+```{.bash .numberLines startFrom=""}
+$ touch mynewfile           # create empty file
+```
+
+There are many more ways to write to files.
+
+
+### Read
+
+Type `less` to **view** a textfile.
+
+```{.bash .numberLines startFrom=""}
+$ less myfile.txt    # exit with "q"
+
+```
+
+Type `head` to view a the **beginning** of textfile.
+
+```{.bash .numberLines startFrom=""}
+$ head myfile.txt
+
+```
+
+Type `tail` to view a the **end** of textfile.
+
+```{.bash .numberLines startFrom=""}
+$ head myfile.txt
+
+```
+
+
+### Cat
+
+Type `cat` to **concatenate** textfiles.
+
+```{.bash .numberLines startFrom=""}
+$ cat myfile
+$ cat myfile1 myfile2 myfile3 ...
+$ cat -n myfile1 myfile2             # line numbers
+```
+
+
+### Delete
+
+Type `rmdir` to **remove** an empty directory.
+
+```{.bash .numberLines startFrom=""}
+$ rmdir myemptydir
+```
+
+Type `rm` to **remove** stuff, be careful!
+
+```{.bash .numberLines startFrom=""}
+$ rm myfile
+$ rm -r mynonemptydir/
+$ rm -f myfile           # force, beware!
+```
+
+
+### Copy & Move
+
+Type `mv` to **move stuff**.
+```{.bash .numberLines startFrom=""}
+$ mv myfile mydir/     # move myfile into mydir
+$ mv mydir1/ mydir2/   # move whole mydir1 into mydir2
+$ mv myold mynew       # rename myold to mynew
+$ mv myfile1 myfile2   # overwrite myfile2 with myfile1 (BEWARE)
+
+```
+
+Type `cp` to **copy stuff**.
+```{.bash .numberLines startFrom=""}
+$ cp myinput myinput.bak   # copy input to input.bak
+$ cp myinput mybackup/     # copy input into backup dir
+$ cp -r mydir1/ mydir2     # copy whole dir1 into dir2
+```
+
+
+### Remote Copy
+
+Use `scp` (secure copy) on your local machine to copy files
+**to/from** a remote machine.
+
+```{.bash .numberLines startFrom=""}
+$ scp mysource mydestination
+$ scp mylocalfile trainee00@vsc4.vsc.ac.at:myvscfile
+$ scp -r mylocaldir trainee00@vsc4.vsc.ac.at:myvscdir
+$ scp trainee00@vsc4.vsc.ac.at:myvscfile mylocalfile
+```
+
+Use `"-r"` to copy whole **directories** to/from.
+
+
+### sshfs
+
+Use `sshfs` on your local machine to **mount** a remote directory at
+your local machine.
+
+```{.bash .numberLines startFrom=""}
+$ sshfs trainee00@vsc4.vsc.ac.at:myvscdir ~/mylocaldir
+```
+
+Type `mount` on your local machine to **view** mounted directories.
+
+```{.bash .numberLines startFrom=""}
+$ mount | grep sshfs
+trainee02@vsc4.vsc.ac.at: on /home/m/tmp type fuse.sshfs (rw,...)
+```
+
+Type `umount` to release the remote directory.
+
+```{.bash .numberLines startFrom=""}
+umount ~/mylocaldir
+```
+
+
+### Filezilla
+
+**Beware**, always use `Logon Type interactive`.
+
+![](pictures/filezilla.png){height=80% style="float: right;"}
+
+
+### WinSCP
+
+![](pictures/winscp.png){height=80% style="float: right;"}
+
+
+### Search
+
+Use `grep` to **search** for patterns in text.
+
+```{.bash .numberLines startFrom=""}
+$ grep foo myfile
+$ grep bar myfile1 myfile2 myfile3
+$ grep -r baz mydir/
+$ grep "if" fizz_buzz.c
+$ grep -r "a" ~
+```
+
+
+### Man
+
+Type `man` to read the **manual**.
+
+```{.bash .numberLines startFrom=""}
+$ man man
+$ man grep
+$ man rsync
+```
+
+Type `"/"` to **search** for keyword within man, `"h"` for **help** or
+`"q"` to **quit**.
+
+### Top
+
+Type `top` to watch all **processes**.
+
+```{.bash .numberLines startFrom=""}
+$ top
+Tasks: 650 total,   3 running, 605 sleeping,  42 stopped,   0 zombie
+%Cpu(s):  5.3 us,  0.8 sy,  0.0 ni, 94.0 id,  0.0 wa,  0.0 hi,
+KiB Mem : 65770984 total,  9477932 free,  9133728 used, 47159324 
+KiB Swap:        0 total,        0 free,        0 used. 52517312 
+  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+
+20259 trainee00 20   0  258224 101832   7456 R 100.0  0.2   0:58.93
+19237 trainee00 20   0  249252  88808   9484 R  84.0  0.1   5:58.72
+...
+```
+
+Type `h` to get **help** within top.
+
+Type `1` within top to watch all **cores**.
+
+
+<!-- ### Top -->
+
+<!-- Type `1t` within top to watch all **cores**. -->
+
+<!-- ```{.bash .numberLines startFrom=""} -->
+<!-- top - 15:59:40 up 55 days,  7:02, 18 users,  load average: 2.75, 2.76, 2.87 -->
+<!-- Tasks: 541 total,   2 running, 538 sleeping,   1 stopped,   0 zombie -->
+<!-- %Cpu0  :   5.6/9.0    15[|||||||||||                                                                   ] -->
+<!-- %Cpu1  :   8.4/15.2   24[|||||||||||||||||||                                                           ] -->
+<!-- %Cpu2  :   7.3/12.6   20[||||||||||||||||                                                              ] -->
+<!-- %Cpu3  :   5.6/11.6   17[|||||||||||||                                                                 ] -->
+<!-- %Cpu4  :   3.3/7.3    11[|||||||||                                                                     ] -->
+<!-- ``` -->
+
+
+### Exercise 2
+
+- [ ] Look around
+
+- [ ] Copy setup script & run it with your **surname**:
+
+    ```{.bash .numberLines startFrom=""}
+    $ cp ~training/vsc_linux_intro.sh ~
+    $ bash ~/vsc_linux_intro.sh myname
+    ```
+
+- [ ] Move into `vsc_linux_intro_myname`
+
+- [ ] Make a directory `foo`
+
+- [ ] Delete the directory `delete_me_empty`
+
+- [ ] Delete the directory `delete_me_nonempty` with the help of **man**
+
+- [ ] Copy the `vsc_linux_intro_myname` to your computer with **scp/rsync**
+
+- [ ] Mount `vsc_linux_intro_myname` on your local machine with **sshfs**.
+
+
+### Ownership and Permissions
+
+Type `ls -lh` to **view** ownership and permissions of stuff.
+
+```{.bash .numberLines startFrom=""}
+$ ls -lh
+permission # user     group  size date   time  name
+drwxr-xr-x 4 training p70824 4.0K Feb 23 19:41 empty_dir
+lrwxrwxrwx 1 training p70824   11 Feb 23 19:41 link... -> ./empty_dir
+-rw-r--r-- 1 training p70824  375 Feb 23 19:41 fizz_buzz.c
+...
+```
+
+Here `rwxr-xr-x` means the **permissions**, with **r**ead, **w**rite,
+   e**x**ecute.
+
+1. `user` can `rwx`
+2. `group` can `rx`
+3. `others` can `rx`
+
+Here all belongs to the is the **user** `training` (owner) and the
+**group** `p70824`.
+
+
+<!-- ### Ownership -->
+
+<!-- Type `chown` (change owner) to change **ownership** of stuff. -->
+
+<!-- ```{.bash .numberLines startFrom=""} -->
+<!-- $ chown myuser myfile -->
+<!-- $ chown -R myuser:mygroup mydir -->
+<!-- $ chown me foo.cc -->
+<!-- ``` -->
+
+
+### Permissions
+
+Type `chmod` (change mode) to **change** permissions of stuff.
+
+```{.bash .numberLines startFrom=""}
+$ chmod myoption myfile
+$ chmod -R myoption mydir
+$ chmod +x myexecutable
+$ chmod u=rwx,g+x,o-rwx myfile
+```
+
+Where `u,g,o` means **u**ser, **g**roup and **o**thers.
+
+
+### Size & Space
+
+Type `du` (disk usage) to view the **size** of stuff.
+
+```{.bash .numberLines startFrom=""}
+$ du mydir
+$ du -h myfile1 myfile2    # human readable output
+$ du -s mydir              # summarize
+```
+
+Type `df` (disk free) to view the **free space** of the whole system.
+
+```{.bash .numberLines startFrom=""}
+$ df
+$ df -h        # human readable output
+$ df -t nfs    # only list filesystems of a type
+```
+
+**Beware**, you cannot have more files than the **maximum number** of
+files at `VSC`!
+
+
+### Redirects
+
+Use `">"` to redirect, or `">>"` to append **output** stream to a
+**file**.
+
+```{.bash .numberLines startFrom=""}
+mycommand > mystd.log      # redirect "stdout" to a file
+mycommand >> mystd.log     # append "stdout" to a file
+mycommand 2> myerr.log     # redirect "stderr" to a file
+mycommand 2>> myerr.log    # append "stderr" to a file
+mycommand 2>&1             # redirect "stderr" to "stdout"
+```
+
+Use `"<"` to redirect a **file** to the **input** stream of a program.
+
+```{.bash .numberLines startFrom=""}
+mycommand < myconfig       # redirect a file to "stdin"
+```
+
+
+### Pipe
+
+Use `"|"` to write output stream **into** the input stream of another
+process.
+
+```{.bash .numberLines startFrom=""}
+mycommand1 | mycommand2
+mycommand1 | mycommand2 | mycommand3 | ...
+mycommand | grep foo      # pipe "stdout" into "grep"
+df -h | grep data         # show disk free of data fs
+ls | grep "foo" | head    # first "foo" in current dir
+```
+
+
+### Manipulate Streams
+
+Use `sed` (stream editor) to manipulate text, like **substitute
+words**.
+
+```{.bash .numberLines startFrom=""}
+$ mycommand | sed "myoption"
+$ mycommand | sed "s/foo/bar/"    # replace foo with bar
+```
+
+Use `awk` to manipulate structured text, like show **columns**.
+```{.bash .numberLines startFrom=""}
+$ mycommand | awk '{myoption}'
+$ ls -l | awk '{print $1}'            # print column 2 of every line
+$ df | awk '{print "hello", $5, $3}'  # print hello, column 5 and 3
+```
+
+
+### Alias
+
+Use `alias` to define an **abbreviation** for commands.
+
+```{.bash .numberLines startFrom=""}
+$ alias myalias='mycommand myoptions'
+$ alias ll='ls -alh'
+$ alias rm='rm -i'
+```
+<!---$ alias myproject='cd $myprojectdir; make && ./myproject' -->
+
+Now you can use the **alias** instead.
+
+```{.bash .numberLines startFrom=""}
+$ ll           # Same as "ls -alh"
+$ rm           # Same as "rm -i"
+```
+<!--- $ myproject    # Same as "cd $myprojectdir; make && ./myproject" -->
+
+Type `alias` to show all **defined** aliases.
+
+
+### Escapes & Quotes
+
+1. Backslash escape:
+
+   Escapes a single character, that would have a special meaning.
+   
+   ```{.bash .numberLines startFrom=""}
+   $ mycommand this\ is\ a\ single\ parameter
+   ```
+2. "Double Quotes":
+
+   Does some **wordmagic**: Escape all whitespace characters, expand
+   variables, etc.
+   
+   ```{.bash .numberLines startFrom=""}
+   $ mycommand "$HOME will be /home/myuser"
+   ```
+3. 'Single Quotes':
+
+   Every character is treated **literally**.
+   
+   ```{.bash .numberLines startFrom=""}
+   $ mycommand '$HOME will be $HOME'
+   ```
+
+
+### Variables
+
+Use `"="` to **set** information as a variable.
+
+```{.bash .numberLines startFrom=""}
+$ myvar=myvalue
+$ foo=bar
+```
+
+Now use `"$"` to **get** a variable.
+
+```{.bash .numberLines startFrom=""}
+$ mycommand $myvar
+$ echo $foo
+```
+
+**Beware**, bash variables are untyped.
+
+
+### Environment Variables
+
+**Environment variables** are visible for all programs.
+
+Use `export` to **set** a variable as environment variable.
+
+```{.bash .numberLines startFrom=""}
+$ export myvar=myvalue
+$ export LANG=en_US.UTF-8
+```
+
+**Beware** if this variable already exists, you **overwrite** it!
+
+```{.bash .numberLines startFrom=""}
+export PATH="$HOME/bin/:$PATH"
+```
+
+Overwrite `PATH` to **add** a directory with your programs/scripts.
+
+
+### Environment Variables
+
+Type `env` to **view** all set environment variables
+
+```{.bash .numberLines startFrom=""}
+$ env
+```
+
+Now use `"$"` to **get** a environment variable.
+
+```{.bash .numberLines startFrom=""}
+$ mycommand $myvar
+$ echo $LANG
+```
+
+Use `unset` or `env -u` to **delete** an environment variable.
+
+```{.bash .numberLines startFrom=""}
+unset LANG    # no "$" here!
+env -u LANG   # no "$" here!
+```
+
+
+### Environment Variables
+
+Some exemplary environment variables:
+
+```{.bash .numberLines startFrom=""}
+HOME              # home directory
+PATH              # program paths, in priority order
+LIBRARY_PATH      # libraries to link by the compiler
+LD_LIBRARY_PATH   # libraries to link at runtime
+```
+
+
+### Wildcard
+
+Use `"*"` as a placeholders for **any number** of characters.
+
+Use `"?"` for **any single** character.
+
+```{.bash .numberLines startFrom=""}
+$ ls *.pdf         # list all pdf files
+$ less readme.???  # read readme regardless of file type
+$ cp * mydir/      # copy eveything into mydir
+```
+
+There are a lot of others, like `"^"` or `"$"` for beginning and end.
+
+
+### Exercise 3
+
+- [ ] Write your name into a text file `myname` using `echo`
+
+- [ ] What is the size of **all** the files in this directory?
+
+- [ ] How much space is left on your `$HOME` and on the `/home` file system?
+
+- [ ] Delete **jpg** files inside directory `delete_only_jpg` **at once**
+
+- [ ] Combine the files inside directory `cat_together` to **one** new file
+
+- [ ] Write your name in the file `try_to_write_to_me`
+
+- [ ] Define the **variable** `NAME` using your surname
+
+- [ ] Export `NAME` as an **environment variable**
+
+- [ ] Delete the **environment variable** `NAME`
+
+
+### Editor
+
+![](pictures/nano.png){height=80% style="float: right;"}
+
+
+### Nano
+
+Use `nano` to **read and write** text files.
+
+- No **mouse**!
+
+- **Search** with `<CTRL>-W`
+
+- **Search & replace** with `<CTRL>-\`
+
+- **Cut** line with `<CTL>-K`
+
+- **Paste** line with `<CTL>-U`
+
+- **Undo** with `<ALT>-U`
+
+- **Save & quit** with `<CTRL>-X`
+
+Complicated editors like **vim** are more powerful.
+
+
+### Scripting
+
+Write a shell script to run a **sequence of commands**, like a cooking
+recipe.
+
+```{.bash .numberLines startFrom=""}
+#!/bin/bash
+
+echo "foo bar"
+
+mkdir mydir
+```
+
+Call `bash` to execute a shell script.
+
+```{.bash .numberLines startFrom=""}
+$ bash myscript.sh
+```
+
+Use `chmod +x`, then call your script directly with `./myscript`.
+
+
+### Scripting
+
+Like a cooking recipe, your shell script will **continue**, even if a
+command **fails**.
+
+**Beware, do not try this at HOME!**
+
+```{.bash .numberLines startFrom=""}
+#!/bin/bash
+
+cd mynotexistingdir
+
+rm -rf *
+```
+
+**Beware, do not try this at HOME!**
+
+What could happen if you executed this horrible example?
+
+
+### Shebang
+
+Write a shebang in the first line of your script to tell the shell
+your **language**.
+
+```{.bash .numberLines startFrom=""}
+#!/bin/mylanguage
+echo "written in foo"
+```
+
+```{.bash .numberLines startFrom=""}
+#!/bin/bash
+echo "written in bash"
+```
+
+```{.python .numberLines startFrom=""}
+#!/bin/python
+print "written in python"
+```
+
+
+### Loop
+
+Use **loops** in `bash` scripts to loop over files, numbers.
+
+```{.bash .numberLines startFrom=""}
+for i in *
+do
+  echo $i
+done
+```
+
+```{.bash .numberLines startFrom=""}
+while true
+do
+  echo "annoying hello world"
+  sleep 1
+done
+```
+
+Or even in **one line**, separated by semicolons, in terminal.
+
+```{.bash .numberLines startFrom=""}
+$ for i in {1..5}; do echo $i; done
+```
+
+
+### Expansion
+
+Use **brace expansion** in `bash` to, well  expand braces.
+
+```{.bash .numberLines startFrom=""}
+$ echo {a,b,c}1
+a1 b1 c1
+
+$ echo a{1..9}z
+a1z a2z a3z a4z a5z a6z a7z a8z a9z
+
+$ echo {a..z}
+a b c d e f g h i j k l m n o p q r s t u v w x y z
+```
+
+
+### If/else
+
+Use `if/else` in `bash` scripts to make quick **yes/no** decisions.
+
+```{.bash .numberLines startFrom=""}
+if [ $myvariable == 0 ]
+then
+    emycommand1
+elif [ $myvariable == 1 ]
+then
+    mycommand2
+else
+    mycommand3
+fi
+```
+
+
+### Case
+
+Use `case` in `bash` scripts when a single variable can **many
+values**.
+
+```{.bash .numberLines startFrom=""}
+case $myvariable in
+    0)
+        mycommand1
+        ;;
+    a)
+        mycommand2
+        ;;
+    *)
+        mycommand3
+        ;;
+esac
+```
+
+
+### .bashrc
+
+Write a `.bashrc` in your `$HOME`, a script that gets executed
+every time you log in.
+
+```{.bash .numberLines startFrom=""}
+#!/bin/false
+
+# define aliases
+alias l='ls -1Bhl'
+alias sq='squeue -u $USER'
+alias rm='rm -i'
+
+# add your own binary directory
+export PATH="$PATH:$HOME/bin"
+```
+
+An **example** is available at `~training/bashrc_recommended`
+
+Call `source ~/.bashrc` to reload changes.
+
+
+### Exercise 4
+
+- [ ] Write your name in a file using **nano**
+
+- [ ] Define and run an **alias**
+
+- [ ] **Read & run** the shell script `all_numbers_from_to.sh`
+
+- [ ] **Read & run** the shell script `one_string_two_words.sh`
+
+- [ ] Test different `for j in ...` in `one_string_two_words.sh` using **nano**
+
+- [ ] Write a shell script that **makes a directory** `foobar`
+
+- [ ] Write a shell script that **makes 100 files**
+
+- [ ] **Compile** `fizz_buzz.c` and **run** the resulting program `a.out`
+
+
+## Bonus Content
+
+
+### Remote Sync
+
+Use `rsync` (remote sync) on your local machine to **synchronise**
+files with remote machine. `Rsync` is like a more complicated but more
+powerful `scp`.
+
+```{.bash .numberLines startFrom=""}
+$ rsync myoptions mysource mydestination
+$ rsync mylocalfile trainee00@vsc4.vsc.ac.at:myvscfile
+$ rsync trainee00@vsc4.vsc.ac.at:myvscfile mylocalfile
+$ rsync -a mylocaldir/ trainee00@vsc4.vsc.ac.at:myvscdir
+```
+
+The flag `"-a"` (archive) syncs whole directories recursively yet
+preserves symbolic links, special and device files, modification
+times, groups, owners, and permissions, but needs root.
+
+Without the trailing slash in `"mylocaldir/"` rsync places the whole
+directory inside the remote directory `myvscdir/mylocaldir/myfiles`.
+
+
+### Remote Sync
+
+Use the `"-n"` flag with `rsync` to test your command without copying
+anything.
+
+```{.bash .numberLines startFrom=""}
+$rsync -anv mylocaldir/ myvscdir
+
+sending incremental file list
+./
+myfile1
+myfile2
+myfile3
+...
+```
+
+Use the `"-v"` flag (verbose) with `rsync` to get more information.
+
+### Editors
+
+Editors can
+
+- Read and write
+
+- Copy and paste
+
+- Search and replace
+
+Examples
+
+- `nano`: simple and super easy
+
+- `emacs`: a lot of magic using `<CTRL> <ALT> <SHIFT>`
+
+- `vim`: every letter is a command (complicated)
+
+
+### Nano
+
+::::: columns
+::: column
+
+Use `nano` if you are new to linux.
+
+- **search** with `<CTRL>-W`
+
+- **search & replace** with `<CTRL>-\`
+
+- **cut** line with `<CTL>-K`
+
+- **paste** line with `<CTL>-U`
+
+- **undo** with `<ALT>-U`
+
+- **save & quit** with `<CTRL>-x`
+
+:::
+::: column
+
+![](pictures/nano.png){height=50% style="float: right;"}
+
+:::
+:::::
+
+
+### Emacs
+
+::::: columns
+::: column
+
+Use `emacs` if you find `nano` boring.
+
+- **search** with `<CTRL>-s`
+
+- **stop** with `<CTRL>-g`
+
+- **undo** with `<CTRL>-"/"`
+
+- **find and replace** with `<ESC> %`
+
+- **save** with `<CTRL>-x <CTRL>-s`
+
+- **quit** with `<CTRL>-x <CTRL>-c`
+
+:::
+::: column
+
+![](pictures/emacs.png){height=50% style="float: right;"}
+
+:::
+:::::
+
+
+### Vim
+
+::::: columns
+::: column
+
+Use `vim` if you find `emacs` boring.
+
+1. | Type `<ESC>` to go into normal mode 
+   | **Every letter** you type is a **command**!
+
+2. | Type `i` for insert mode 
+   | A **letter** is just a **letter**
+
+3. | Type `":"` for command mode
+   | Enter your command to **execute**
+
+:::
+::: column
+
+![](pictures/vim.png){height=50% style="float: right;"}
+
+:::
+:::::
+
+
+### Vim
+
+Vim examples
+
+- **delete** with `d`
+
+- **search** with `"/" foo`
+
+- **undo** with `u`
+
+- **find and replace** with `":" s/foo/bar/c`
+
+- **save** with `":" w`
+
+- **quit** with `":" q`