The Linux Command Line
by William E. Shotts, Jr.
A comprehensive and highly-regarded book for learning the Linux command line. The author makes the command line accessible to beginners while covering advanced topics. A free online version is available.
More resources on Linux Command Line
Advanced Bash-Scripting Guide
Free book-length guide to Bash scripting by Mendel Cooper, moving from basic scripts through variables, quoting, loops, functions, arrays, regular expressions, I/O redirection and subshells, with hundreds of annotated example scripts. Readers learn to write and debug nontrivial shell programs.
Learn Linux TV
This YouTube channel offers a wide range of Linux tutorials, including many focused on the command line. The content is practical and well-explained, suitable for various skill levels.
Linux Journey
A popular and free interactive online course that teaches the fundamentals of the Linux command line. It's structured with clear modules and exercises, making it excellent for self-paced learning.
The Missing Semester of Your CS Education
Covers the practical tools computer science courses rarely teach: the shell and scripting, the command-line environment, editors such as Vim, data wrangling, Git, debugging and profiling, and metaprogramming. Each lecture has a video, full notes and exercises, leaving learners efficient at everyday terminal work.
Operating Systems Fundamentals (Linux)
Introductory Linux administration course with virtual-machine labs and a capstone, covering shell basics, file systems and paths, text processing, users and groups, permissions and ownership, jobs and processes, partitions and system services. Learners can administer a Linux machine from the command line.