ls is used to get a list of files/folders in the current directory:

ls -l gives a vertical list with a lot of information(not covered here)



if you want to get a list from another directory, pass the path after the command, like:

ls -l /usr/bin

if you want to see hidden files too, simply add -a like: ls -l -a or ls -la,hidden files/folders

are those with a dot prefix:


for all the options read the manual with man ls.


pwd says the folder where you are:


more info with man pwd.


cd is used to get inside/outside of a folder like: cd /home/user/Desktop, if you want to step back

of one to go to the /home/user folder simply type cd .., for more commands type man cd.


cp is used to copy files (folders with -r) from a folder to another:

cp /home/user/Desktop/file1.txt /home/user/Documents copies one file only


you can copy an entire folder with cp -r /home/user/Desktop/mp3 /home/user/Music, now

you have a the folder mp3 inside the folder Documents


if you want the content of the mp3 folder inside the Music folder use

cp /home/user/Desktop/mp3/* /home/user/Music. ls -l shows the content:


more options on the manual man cp.


mv move (used for rename too) files/folders, mv file1 file2 renames file1 to file2 mv file1 /home/user/Documents moves the file from current folder to Documents folder.

Type man mv for more options.


free check the RAM / swap usage, free -om displays values in megabytes:


more info with man free.


df displays disks usage, df -h displays auto Kilo/Mega/Gigasuddivision:


check man df for more info.


touch creates a file, touch myfile creates a file named myfile in the working derectory.

more option in the manual man touch.


mkdir creates a folder, mkdir newfolder creates a folder named newfolder in the actual directory.

more option in the manual man mkdir.


chmod changes the permissions in witch users interact with a file, for example you are the owner of the file and you have read and write permission, standard users shouldn’t write and execute that file.

You can pass 3 paramaters (numbers) which are combined values of:

4 read

2 write

1 execute

so you execute chmod 744 myfile which means4+2+1(7) for the owner, 4 for the usergroup, 4 for the world.

When you execute ls -l the left part of the info gives you the explanation of what is going on

-rwxr--r-- 1 embedded users 0 Dec 6 00:04 myfile

- means file (folder would be d) rwx is read/write/execute for the owner, r-- read only for the usergroup, r-- read only for the world, date and time of ‘last modified’ and filename.

chmod --help and man chmod give you more info.


date prints date and time, date --help and man date for more info.


cal prints the calendar.