2022
Barrett - Efficient Linux at the Command Line
    6148C61A6A2B6A3DCD75BC82D9776E81
    EF0BB256B59813BCEC9C11D8DA34BE6B
    798656CB57D9C3F7E06AB3CF2932CB82
    C2F1FB8E674CAD21C7CDC579EF42FF06
2021
Janssens - Data Science at the Command Line
    9E06296DC46CAA41AFD7F7A98C23B9B5
????
Kiselyov - Cooper - Advanced Bash Scripting Guide
    http://personal.riverusers.com/~thegrendel/
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    796F51474CC30A349BCBF61389065E2D