Super basique mais je cherche a chaque fois
ls
stands for: (list)
aussi : ls -a

cd
stands for: (change directory)
aussi : cd ..

mv
stands for: (move)

rm
stands for: (re move)

su
for admin mode

nano
for editing file
(ctrl x to save and exit)

Meme erreur
Insufficient permissions: "data/log.txt" file is not writable
et cette commande a marché :
/var/www/shaarli/data$ sudo chmod 777 log.txt

(les permissions : https://linuxhandbook.com/chmod-calculator/ )