As Postgres has moved away from a Unix-dominated environment since 2005, there has been decreasing use of Unix shell scripts and increased reliance on Perl, particularly for building Postgres from source. With increasing Perl usage, I realized I had to learn it. I have finally learned Perl with the help of three great books, two of which are readable online:
These are concept-oriented books, which is perfect for me, rather than example-led books. Learning Perl was also a requirement for developing PgLife.