# Mirar el espacio en disco
$ df -h
# Mirar el espacio en memoria
$ free -h
# Mirar la ip
$ ip address

tar -zcvf archive-name.tar.gz directory-name
# Extract
tar -zxvf prog-1-jan-2005.tar.gz
# Extract in a particular directory
tar -zxvf prog-1-jan-2005.tar.gz -C /tmp

alias emacs="emacs -nw"

apt install <package>

sudo apt-get install opera-stable –reinstall

sudo apt-get purge opera-stable

sudo apt-get source opera-stable

apt-cache search keyword

apt-cache search .

apt list –<param> <?package>, param=(installed|upgradeable|all-versions)

apt-cache policiy <package>

sudo apt-cache show “opera-stable”

apt install <package>=<version>

You just need to do apt-get install –only-upgrade <packagename>. This will upgrade only that single package, and only if it is installed. If you wish to install the package if it doesn't exist, or upgrade it if it does, you may leave out –only-upgrade.

Edit apt-conf file (or create a new one if you have no one yet) using the editor of your choice.

sudo nano /etc/apt/apt.conf

Add this line to your /etc/apt/apt.conf file (substitute your details for yourproxyaddress and proxyport).

Acquire::http::Proxy "http://yourproxyaddress:proxyport";

• Order ls: ls -t
• For reverse order (most recent at bottom): ls -tr

Disk usage.

• In MB: df -m
• In a human readable format: df -h

Change the owner:

• For changing the user and the group recursively: chown www-data: -R .

To display mounted data:

findmnt

Other options:

# List format
findmnt -l
# Showing disk usage
findmnt –D
# fstab
findmnt -s
# filter by type:
findmnt -t ext4
findmnt -t xfs
# filter by device:
findmnt -S /dev/vda3
# filter by mounted point:
findmnt -T /

To see the last lines of a file.

• For maintaining it reading it use -f parameter.

To see a tree of only directories until 3rd level:

tree -d -L 3

The next will also give you the disk space used:

tree --du -h

To send output as parameters:

$ echo 'one two three' | xargs mkdir
$ ls
one two three

Script example for creating .cbz files from folders inside the current path:

ls -1 | xargs -I {} zip {}.cbz -r {}

zip -r app.old.zip app/

• htop → easy to use top command
• glances → easy to use monitoring command
• tree → to show the folder tree
• watch → wait showing a command output
• shutdown now → turn the computer off
• i3lock -c 000000 → turn the screen off
• xdotool → for sending via command line keys, texts… to the GUI

!<command> will execute the <command> with the parameters you executed last time: remember the command name e.g. !ls will execute your last “ls -lrt” , !vim will open your last file without typing full command.

!! will execute the last command.

cd - goes to the prev visited path.

pushd and popd create a stack of path. If you arrive to a path and want to add it on the stack, you will do pushd .

With dirs command you can see the stack.

You can add this to .bashsrc to add cd + as ot do popd. So when you visit a path you auto add pushd's:

cd()
{
  if [ $# -eq 0 ]; then
    pushd "$HOME" > /dev/null
  elif [ $1 = "+" ]; then
  	popd > /dev/null
  else
    pushd "$@" > /dev/null
  fi
}

It's not recommended to do this for root; it could close all the current running processes.

pkill -KILL -u user

ls -1 $* | xargs -I {} zip "{}.cbz" -r "{}"

You can do Ctrl+l to clear the screen which is the same than clear command.

To actually reset the scroll and everything you will use the reset command.

My favorite new one that I have been using a lot:
  function cheat() {
      curl cht.sh/$1
  }
It queries the cht.sh cheatsheet of various Unix commands. 'cheat tar' prints:
  # To extract an uncompressed archive:
  tar -xvf /path/to/foo.tar
  
  # To create an uncompressed archive:
  tar -cvf /path/to/foo.tar /path/to/foo/
  
  # To extract a .gz archive:
  tar -xzvf /path/to/foo.tgz
  
  # To create a .gz archive:
  tar -czvf /path/to/foo.tgz /path/to/foo/
  ...