Linux is an open-source operating system with a huge number of distributions, some of them:
Ubuntu
Linux Mint
CentOS
Fedora
Debian
Most of these operating systems have a graphical interface that provides a wealth of features, but the greatest power of Linux comes with the use of a command-line interface (CLI)
For this reason, it is useful to know some of the most common Linux CLI commands.
Commands for working with files
cd
command
Many times, we can change the active directory we are currently working with. This is done with the cd
command.
cd /home/user/folder1
# Current directory will be /home/user/folder1
ls
command
The ls
command is used to display the contents of the current directory.
ls
# Output example
Desktop Documents Downloads Music Public
Temp .gitconfig
ls -R # list all the files in the sub-directories
ls -a # show hidden files
ls -al # list all info's about a file (size, owner ...)
pwd
command
The command tells us which is the currently active directory.
pwd # return the current directory
# output example
/home/user/folder1
cat
command
Perhaps the most commonly used command in Linux, as it allows you to create, combine files.
cat > file # create file with name file in current directory
cat file1 file2 > file3 # joins file1 and file2 and create output file3 in current directory
cp
command
cp
command disables copying a file from the current directory to another.
cp document.txt /home/user/Documents # copy document.txt from current directory to folder called Documents
mv
command
mv
allows you to move files.
mv document.txt / home / username / Documents # move document.txt from current directory to folder called Documents
You can also rename files with this command.
mv oldname.txt newname.txt # rename file from oldname.txt to newname.txt in the current directory
mkdir
command
This command creates new folders.
mkdir Archive / Documents # create folder called Documents from current directory
mkdir -p Archive / 2021 / Documents # create folder 2021 between folders Archive and Documents
rmdir
and rm
command
Commands can be used to delete folders.
With rmdir we can only delete empty folders.
With rm, you can delete the entire folder (check before use because it is not possible to restore the deletion).
rmdir NotusefulFolder # remove NotusefullFolder (it is empty) from the current directory
rm Folders / NotInUse # remove all files and folders in folder NotInUse from the current directory
rm -r NotUsefulFolder # command equal to rmdir
touch
command
The command allows you to create new files.
touch file.txt # create a file in the current directory
find
command
Used to search for a specific file.
find
cat
command
This command allows us to print the contents of a file.
cat
head
command
Display us the first 10 lines of the file.
head file.txt
tree
command
Return filesystem directory tree.
tree
Setup commands
sudo
command
Abbreviation for "SuperUser Do", with this command we can execute commands that require administrative authority.
sudo <SOME_ACTION> # In the next step you must input the password for the root/admin user
df
command
Shows us disk usage in KB and percent.
df # Return disk usage in KB
df -m # Return disk usage in MB
kill
command
The Kill command allows you to stop a specific process.
ps # return list of active processes
kill 11111 #kill process with PID 11111
zip
and unzip
commands
They allow us to create compressed zip files and expand zip files.
unzip zipped_file.zip # command unzip zipped_file.zip file
ping
command
The command is used in most cases when we want to check if a device is active on the network
ping hashnode.com
hostname
command
The command tells us the name of the device
hostname # return hostname of the device
# example output
server
useradd
and passwd
command
useradd
allows us to create a new user. Passwd allows us to change or set a password.
useradd NewUserName # create new user
userdel UserName # delete user
passwd UserName # can set a password if doesn't exist or change if exists
wget
command
A very useful command to download files.
wget DownloadFileURL # download file in current directory
free
command
After giving us the amount of memory used.
free -h # return usage of memory - RAM (human-friendly numbers and units)
shutdown
and reboot
command
Simple commands - the sessions already name what they learn.
shutdown # shutdown computer
reboot # reboot computer
Maybe if you have read in detail and gotten to know the Windows terminal, then you have noticed some commands are the same.
Of course, there are even more of these commands, but I mentioned the most commonly used ones. If I forgot any, and you find it important to use in Linux, mention them in the comments ๐.