Linux

Using a Linux Operating System, there is a high level of customization, depending on your preferences or needs. One important thing is to create aliases to the most common commands in order to optimize the time you use. In mi case, I love to use .. instead of cd .. or update to update all my Linux software pending updates. Here I put my list of aliases for Ubuntu (based on Debian) or CentOS (based on RHEL) distribution. It is not big but it is what I mostly use in the servers I have with Linux. ...

The Linux command line is a great tool. Today I’ll like to share a method to get Geographical IP information with one command, using curl and the tool of ipinfo.io. It is as easy to use this command: $ curl ipinfo.io/<IP Address> Here you have an example: You will have these parameters: IP City Region Country Loc (Coordinates) Org Postal Timezone If you want to get information about the Public IP Address you use to go to The Internet, you could execute the command this way: ...

I have faced an issue in a web server using NGINX while trying to upload a file using wordpress. In the nginx error log I saw the error “Client intended to send too large body” in this entry: $ tail -f /var/log/nginx/*error*.log 2020/09/01 14:31:04 [error] 884#884: *126565 client intended to send too large body: 1195619 bytes, client: 55.173.250.46, server: test.com, request: "POST /wp-json/wp/v2/media?_locale=user HTTP/2.0", host: "test.com", referrer: "https://test.com/wp-admin/post.php?post=2460&action=edit" ...

By default, Ubuntu desktop installation will provide DNS resolving configured, however in Ubuntu server installation avahi-daemon (or mdnsresponder) is needed to be installed to provide local LAN DNS resolution. In my case, i found the error “Temporary failure in name resolution” when I tried to resolve a machine of my LAN from Ubuntu. yvoictra@zoar:~$ ping erie.local ping: erie.local: Temporary failure in name resolution To solve this issue, there is no need to install a DNS server in the LAN. We can use the mDNS (Multicast Domain Name System) protocol. This protocol is used to resolve host names in a small network (LAN). The mDNS service can be contacted using UDP queries over port 5353. The mDNS protocol is published as RFC6762 and implemented by the Apple Bonjour and avahi-daemon services. ...

The sudo command allows users to run programs with the security privileges of another user, by default, the root user. First if all, the user should be created in the system if it doesn’t exists yet. On Ubuntu systems, by default members of the group sudo are granted to sudo command access. Once the user is created, from root user, or a user with sudo access, you have to execute this command to add the user to sudo group. ...

Monitoring network traffic or bandwitdh usage is a must in a SysAdmin tasks. There are many differents tools to manage this monitoring, but one of my favorites is vnStat. The main advantage of this tool is the simplicity of its usage. Installation With Ubuntu, the way to install this tool is with apt. sudo apt install vnstat First steps Once installed, it is important to know which interfaces are going to be monitoried. For this, you can use next command ...

First step is to check the status of the interfaces. For this, we will use the net-tools package. sudo apt install net-tools Then, we can see the interfaces status ifconfig -a In my case, I have this status of my interface wlan0: ubuntu@ubuntu:~$ ifconfig -a wlan0 wlan0: flags=4098<BROADCAST,MULTICAST> mtu 1500 ether dc:a6:32:6c:xx:xx txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 ...

In order to create a new user in a Linux Ubuntu distribution from terminal, you have to use this command. sudo adduser username After this, the system will ask you some parameters included the password. [23:43:24] ubuntu|zoar:~$ sudo adduser yvoictra Adding user `yvoictra' ... Adding new group`yvoictra' (1001) … Adding new user `yvoictra' (1001) with group`yvoictra' … Creating home directory `/home/yvoictra' ... Copying files from`/etc/skel' … New password: Retype new password: passwd: password updated successfully Changing the user information for yvoictra Enter the new value, or press ENTER for the default Full Name []: Yvoictra Room Number []: Work Phone []: Home Phone []: Other []: Is the information correct? [Y/n] y [23:46:40] ubuntu|zoar:~$ ...