Notes

mkdir summer winter - napravivme dva foldera winter and summer
sea praime mkdir summer/seeds - vo summer napraivme folder seeds


rmdir and rm both deletes files or directories but rm brishe i ako ne e empty a rmdir samo ako e empty.


Touch - to create empty file.


mv Stuff/STUFF- go renamenavme od so mali u se so caps.


Cp- copy files; cp -r to copy whole folder.


head SongOfMyself.txt - prints the first 10 lines of the file SOM.
but we can say head SongofMyself.txt -n 100 - will provide us with the first 100 lines of the folder.


tail SongOfMyself.txt - prints the last 10 lines of the file SOM.
but we can say tail SongOfMyself.txt -n 100.
- will provide use with the last 100 lines


cat SongOfMyself.txt - prints the contents of that file to my standard output (Kade si home desktop Bla-Bla posle fata saat)
cat will give us the whole file of SOM - the whole song.
- cat gives us the entire file
- cat contents (entire file)
- if we provide cat with more files will give the contents to all of the files
- cat -n SongOfMyself.txt - gi redi so reden broj site stihovi od pesnata

less shows the content stored inside a file.
kako cat ke ja dae cela pesna samo strana po strana i ustvari motash edna strana at a time
- less SongOfMyself.txt
- b gore one page at a time
- end of the file capital G
- lowercase g to the top


echo - prints the output the argument passed to it.
$echo “HII”
print out: HII
echo “FUCKU” > nikola.txt
instead of printing fucku to the terminal it will redirect it to the folder Nikola.txt.
- za da dodademe use neso na Nikola fileot pisuvame echo “FuckU=Mrsh” >> Nikola.txt stavame dve >> vakvi


Wc useful information about a file or input it receives via pipes.
- wc SongOfMyself.txt
output: 1757 15767 87022 SongOfMyself.txt
- 1757 means number of lines
- 15767 means number of words
- 87022 means number of bytes
-l means just lines
-m characters
-c bytes
-w words
wc -l SongOfMyself.txt
1757 SongOfMyself.txt - outcome
- output of one command is input of another command through pipping
ls -l | wc (piping e so prava linija)


cat groceries.txt butcher.txt | wc -l > number.txt
- cat gi combinenuva dvete.txt | znaci piping i wc l da kazhe broj na lines go redirect ova celo u file number.txt so znaci nema da isprinta tuku ke napravi


sort
$sort everything.txt - will alphabetically sort by default.
we can redirect the file as:
$sort everything.txt > sortedEverything
-f means ignore case (upper or lower case because automatically upper case goes first)
to sort numbers, we say $sort -n nums (the file name in this case nums) from smallest to largest and for vice versa we write $sort -nr nums


uniq
to sort lines of text. removes adjacent duplicate values (meaning, one below the other to be the same name/value)
$sort favFlavors.txt | uniq - the result would be all the values sorted alphabetically but each only once because of the | uniq.
$sort favFlavors.txt | uniq - d = only the duplicates will be here.
you can count how many times each line appears with:
$sort favFlavors.txt | uniq -c
5 chocolates
4 cookies and cream - example output; so, chocolate appeared 5 times.


expansions - special characters
$ vrtena -; echo $PATH ke ni go dae cel pat so kako sme upalile bin min Bla-Bla.
$echo * - gives us every path name in this current folder.
* Means every path
$ echo *.txt - gives us every path name that ends with .txt.
? - any single character ???? - any four characters in a row
$ echo *.?? anything that must end with dot and two characters, for example if we put *.??? - it will give us all the files that end at dot three characters for example .txt, .zip....

$ rm *.?? - removes all the files that end with dot and two characters.


curly braces
example $echo {a, b, c}.txt it will create every possible combination but with one letter e.g. a.txt b.txt.
{1...99} - every number from 1 to 99.


diff - if you have files with same information, diff will process the files and will tell you the differences.
$ diff favFlavors.txt favFlavors2.txt - outcome: the difference
$diff mentions what is the difference: 3c3 < strawberry --- > strawberry and cream mean the third item from the first (strawberry) was changed to strawberry and cream.

$diff -y means compare on the screen both files.
$diff -u see what's changed.


find - find files or folders matching a particular search pattern.
find. - all files on my computer.
find. name '7' - file that has the 7 as its name.
find. name '*7*' - every file name that has a seven in it.


grep - search files or combine it with pipes to filter the output of another command. Not in the files but inside of them.
$grep green SongOfMyself.txt
outcome: prints every sentence where green is mentioned in the file.
we can also make grep to give us the line numbers:
$ grep -n green SongOfMyself.txt: gives the line number to all of the parts there is green mentioned.

$grep -nC 2 green SongOfMyself.txt - gives two lines after and two lines before the line that has green mentioned in it.

$grep -r "chicken" hello.txt
all files nested somewhere in my desktop, and all contain chicken.


ps - your computer is running at all times tons of different processes. You can inspect them all using the ps command.
view a list of processes initiated by anyone.
ps axww
ps axww | grep "Visual Studio" - prints out all the matches for the visual studio code processes.


top - used to list the processes running in real time. Used to display dynamic real-time information about running processes in the system. (display and update sorted information)
$ top -o mem will highlight the mem part and it will give us sorted information in order of how much memory.


kill - send a variety of signals to a program.
$kill -l will list the different signals that we can send.
$kill <PID> (process ID) - most common way
term - gentlest way to quit something or stop a process.
$kill -9 1125066 (PID) no feedback given but the 9th line is killed.


nano- text editor. directly type characters into the file without worrying about modes.

$nano SongOfMyself.txt - opens the file with edit mode.
^X exit
^ replace
^T to spell
^O Write out
^W search
$ nano NewFile.txt - makes new file and immediate ability to edit.


who- users logged in to the system.
$ who - list of people logged in what time and what date.


su - switch users
$su (followed by some username) - enter password to enter as the username.
$su - Elvis takes me right into Elvis' home directory.


sudo - used to run a command as root.
You can run commands as root by entering your user's password (not the root user password).
$ sudo -i starts a shell as root.

ls -l see who the owner is.
$sudo nano /etc./hosts
[sudo] password for colt - not the root password but the colt's password.
specific users have specific permissions.


passwd - two situations. first is when you want to change your password.
$passwd
changing password for colt.
Current password: ...
New password: ...

man passwd -e expire.
$passwd elvis (can do as root user) - i can change Elvis' password.


chown - change ownership.
$chown <owner> <file>
$chown colt Music/
I can't make myself the owner of someone's directories.
$sudo chown colt Music/

$chown -R <owner> - to recursively change the ownership.
$chown kitty CatStuff/
$sudo chown -R kitty CatStuff/


chmod - to change the permission of a file or directory.
who? u-user g-group o-others a-all of the above
what? - removes the permission + grants permission. = set a permission and removes others.
which? r- read w- write x- execute permission.

$chmod a+r then the file name
$chmod o+r Permission/
$chmod g-r Permission/

$chmod a+rwx SongOfMyself to all we add all permissions.
$chmod a-rwx to all remove all permissions.