A command may need to run under sudo without pausing for a password prompt. NOPASSWD is a sudoers tag that suppresses authentication for commands matched by its policy. I’ll show how to add and validate a narrowly scoped NOPASSWD rule, then how to diagnose a prompt that remains. TL;DR Use visudo to add a NOPASSWD
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Passing a group of values through a shell script calls for a way to store them together. Bash arrays hold multiple values under one variable, with each value available as an array element. This article walks through creating Bash arrays and iterating over their values without splitting entries that contain spaces. TL;DR: Bash arrays keep
Shell Array: Create and Use Bash Arrays Read More »
A command that keeps running can leave you needing to stop its process without affecting a different one. Linux’s kill command sends a signal to a process you select by its process ID, or PID. This article shows how to identify the intended PID and request termination, then check whether the process stopped before escalating.
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Putting files together in Linux means choosing how their contents should appear in the result. The cat command copies each file’s contents into one stream, in the order you name them. You’ll see how to combine files with cat and use redirection to control the destination. TL;DR: Concatenate files with cat Use cat with the
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On Linux, checking which processes are using system resources starts with viewing the process list. htop is an interactive, text-based process viewer that refreshes system and process information in a terminal. I’ll show you how to install htop and use its process list to inspect CPU and memory use. TL;DR Install htop with your distribution’s
htop Linux: Install and Use the Process Viewer Read More »
Linux users checking a computer’s reported hardware details can start with dmidecode. It reads the hardware data recorded in the computer’s firmware table and presents it as labeled information. I’ll show you how to check that dmidecode is available and choose a record type or named value for a query. TL;DR: Use dmidecode to Read
Dmidecode in Linux: How to Use It? Read More »
Creating a keyboard shortcut in Bash means assigning a key sequence to an action at the prompt. Bash’s bind builtin connects that sequence to an editing function, inserted text, or a shell command through Readline, the line editor used at an interactive prompt. In this piece, I’ll show how to test a key binding at
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Ubuntu users can create or extract archives from the command line. The 7-Zip command-line utility creates and opens compressed archives, including .7z files. In this piece, I’ll show how to check and install the Ubuntu package for your release, then use 7z to create and extract an archive. TL;DR Install the Ubuntu package that matches
Ubuntu 7zip: Create and Extract Archives Read More »
A server rename begins by choosing the name Ubuntu should use for the machine. The hostnamectl command sets that system name, while the hosts file can map the name for local lookups. This article walks through changing the hostname and checking whether provisioning or DNS needs a separate update. TL;DR Run hostnamectl set-hostname with the
How to Change Hostname in Ubuntu Server Read More »
To add a line or command output to a Linux file while keeping its current contents, use >>. The >> operator writes after the file’s current end, while > replaces its contents. I’ll show how to use >> for text and command output, then explain how a missing final newline or lack of write access
How Linux Appends Text to Files Read More »