Unix snippets

ls  -a (includes hidden)
    -d (directories)
    -lsh (details + size)
    -R (recursive directories)

cp  -n (no overwrite file)
    -R (recursive copy)

mv  (move and rename)
    -f (transfer large files)

mkdir
rmdir

ps  -aux (show all with details)
    -a (show except group leader)

kill -9 PROCESS_PID
     -l (list of kill signals)

which EXECUTABLE_FILE_NAME (locate file) 

touch

cat FILENAME (display file content)
cat >FILENAME (create file called FILENAME waits for input, ends with ctrl+d)
less FILENAME (navigate large files, exit using q)

lsusb (list usb devices)
cmp FILE1 FILE2 (check if files are different, no output is equal)
alias CMDNAME='NEW COMMAND'
cal (calendar)
history
chmod XYZ FILENAME (X=user, Y=group, Z=other, assigned as a sum of permission)
        0:"no permission"
        1:"execute permission"
        2:"write permission"
        4:"read permission"

        example: "sudo chmod 777 MYFILE" (grant all permissions for all users)

setxkbmap -option caps:backspace