Linux command line - terminal komande

Svaki kompjuter se mnogo lakse upravlja preko tekstualnih komadi u terminalu (onaj crni prozorcic).

Terminal mozete pokrenuti tako sto stisnete Win dugme i pretrazujete Terminal ili pomocu keyboard shortcut Ctrl+T.

Kada se kaze shell, terminal, command line, prompt, console… su sve sinonimu za terminal tj program u kojem kucate komande.

Ok, postoje razliciti terminalni prozori (GNOME Terminal, Konsole, windows terminal) i razliciti shellovi (npr Bourne shell /bin/sh ne podrzava alias, history, tab completion, background tasks)

Linux je CaseSensitive (morate obratiti paznju da li su mala ili velika slova, uglavnom treba koristiti mala slova). Kada postoji razmak (space) u nazivu fajla, onda se mora escapovati ime\ fajla.txt ili staviti u navodnike "ime fajla.txt" (uglavnom treba koristiti donju crtu umesto space)

Bas dobar tutorijal je na Ubuntu Command Line for beginners

Navigation

• pwd (print working directory)
• cd (change directory), cd .. (idi u parent), cd ~/Downloads (idi u home/Downloads)
• mkdir folderName (napravi folder), mkdir -p folder1/folder2/folder3 (napravi parent foldere ako ne postoje)

File manipulation

• cp fileName destinationFileOrFolder (copy), cp ~/Downloads/a.txt . (kopiraj a.txt iz Downloads u trenutni folder), mv fileName destinationFileOrFolder (premesta fajl, tj posle kopiranja ce obrisati fileName)
• rm fileName (remove), rm -r folderName (obrisace folder i sve fajlove unutar njega)
• ls (list), ls a* (izlistaj sve fajlove i foldere koji pocinju sa a), ls -a show all files, including hidden (start with dot eg .bashrc)

Text inspection

• echo Neka recenica komanda za ispisivanje recenice, echo -n without new line at the end without new line
• cat fileName concatenate files
• wc fileName (word count)
• sort fileName (sort)
• uniq remove repeated lines (only consecutive lines, not any duplicated lines)

Strings and special characters

• cat file\ name sprecava specijalno znacenje narednog znaka
• ls 'file name' inside quote it is a single string
• ls "fine name" inside double quote it is single string but ! and $VAR se uvazavaju
• rm find / -name core -print`` unutar ` se zamenjuje rezultatom

Shell redirection

• ls | less pipe komanda prosledjuje output stdout predhodne komande u input stdin za novu komandu
• ls > output.txt znak vece preusmerava output u fajl (ukoliko fajl postoji, sadrzaj ce biti obrisan), ls >> output.txt dodaje output na postojeci sadrzaj fajla, failedCommand >& output.txt preusmerava stdout i stderr u fajl
• cat < fileName preusmerava stdin da se cita iz fajla fileName
• echo << HERE_DOC stanardni ulaz se cita iz istog fajla do reci HERE_DOC (end-of-input)

Multiple commands

• ls;pwd multiple commands, (ls;pwd) > output to group command
• ls \ grep amultiline commands in separate lines use backslash to continue command in new line

Alias

• alias pp=pwd create alias pp for pwd, alias -a show all aliases, unalias pp remove pp alias

Scripts

• source fileName (also . fileName)

Control jobs

• ctrl+c prekida tekuci posao
• kill processId
• logout exit when it is login shell exit [status] exit in any shell
• du > usage & run commad in background
• ctrl+z temporary stop the process, fg foreground, jobs list all jobs

History

• history see previous commands
• !! run previous command
• !ls run last command that start with ls

Users and groups

• su username (switch user), sudo ls run ls as root user and return to normal user

Important files

.bashrc se pokrece u svakom shellu (non login shellu, ali svakako login shell ovo poziva tako da mozemo smatrati da se svakako izvrsava)

Keyboard shortcut

• Up/Down or Ctrl+p/Ctrl+n previous or next command from history
• Ctrl+d logout or exit

Install packages

• sudo apt install packageName

Env

• echo $PATH list of folders where shell look for a command