As a software engineer, learning Linux was the best time investment I've made. Since it's a system that user has to understand and maintain, daily experience feels like adding a drop to the puddle. After long time, the puddle becomes a lake, or even an ocean.

Today as a 30 years old engineer, I still benefit from little chunks of knowledge that I happened to learn years ago, when I was an ambitious beginner. In another blog post, I explain more about why Linux is more pragmatic option for software developers.

In this blog post I'll share less popular but very useful Linux commands I personally use and recommend. If you're on a Macbook, that's fine, because most of the commands I'll mention also exist in OSX.

10. file

Returns information for given file. For example, you can print the size information of an image:

file logo.png

Returns:

> PNG image data, 16 x 16, 8-bit/color RGBA, non-interlaced

9. iotop, powertop, nethogs

How would you monitor what's happening in a Linux system ? These three commands are life savers;

• iotop: Sorts processes by disk writes, and show how much and how frequently programs are writing to the disk.

• powertop: Lists processes by their energy consume. It's a vital command when you're outside, somewhere you can't charge your laptop.

• nethogs: Lists processes by their network traffic.

8. tee

It splits the output of a program, so we can both print & save it. For example, add a new entry to hosts file;

echo "127.0.0.1 foobar" | sudo tee -a /etc/hosts

7. pidof, kill and pkill

These three important commands help you control running programs in your system.

pidof prints out the process id of a running program. For example, below command will output the process ID of nginx:

pidof nginx

You can kill nginx by taking that number and giving to kill command:

kill -USR2 $(pidof nginx)'

pkill is a shortcut command that kills the process matching pattern:

pkill -f nginx

6. tmux

You gotta install tmux if you haven't yet. Tmux is an excellent window and session manager for your terminal.

5. tree

Lists contents of a directory in tree-like format. It has neat options like showing only directories;

tree -d

4. find

This command is a life-saver when we are looking for specific files around dozens of others. I'll cover a few simple use cases of it here.

Example 1: List all CSS files (including subdirectories):

find . -type f -name "*.css"

Example 2: List all CSS or HTML files:

find . -type f \( -name "*.css" -or -name "*.html" \)

3. htop

Famous process monitor. It has a nice, colorful command-line UI. Some useful keybindings:

• \ Filter
• / Search
• , Choose sorting criteria
• k Send kill signal
• u Filter results by user
• t Open/close tree mode
• - and + Collabse / uncollapse selected process tree
• H Turn off displaying threads

2. chroot

Magicians love this command because it opens up a new TTY in given directory. Which means, you can create a folder, set up a new Linux system inside, and switch to that "child system" whenever you want.

Isn't it powerful ?

1. dialog

A very simple and nice way to interact with the user on command-line. For example, this command below shows a nice input box:

dialog --title "Oh hey" --inputbox "Howdy?" 8 55

It exists on both Linux and OSX systems, and supports many other kind of dialogs; message boxes, menus, confirms, progress bars... The installation wizard I coded for Happy Hacking Linux is made with this amazing command!