Incorrect/shuffled index order when running createBookFromReadme.sh

[primeagen-rustaceans]

I wanted to contribute to the project.
Issue/Bug :
Currently the index in the side menu and the index in the URL has a difference of 1.
e.g. The updates page has a index number 1 in side menu but in URL it shows Chapter_0.html.
To rectify this index mismatch. I just awk-ed each Chapter filename after it is generated and increased the index by 1.
e.g. Chapter_0.md -> Chapter_1.md
But every time I am building the project using createBookFromReadme.sh, the SUMMARY.md file is different and generated with shuffled index.
Am I doing something wrong while building.

OS : Ubuntu 22.04
Steps to reproduce :
Modify gcsplit to csplit
Run ./createBookFromReadme.sh