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)

ls-l

 

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:

ls-la

for all the options read the manual with man ls.

 

pwd says the folder where you are:

pwd

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:

mp3

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:

free

more info with man free.

 

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

df

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.