Building a Shell
healeycodes.com
Building a Shell
1–10 of 49 posts
Re: Building a Shell
#2Bit of pedantry but I don't think traditional unix shell (like this) follows repl model; the shell is not usually doing printing of the result of evaluation. Instead the printing happens more as a side effect of the commands.
Re: Building a Shell
#3Building a shell is a great exercise, but honestly having to deal with string parsing is such a bother that it robs like 2/3 of the joy along the way. I once built a very simple one in Go [0] as a learning exercise and I stopped once I started getting frustrated with all the corner cases.
[0] https://github.com/lourencovales/codecrafters/blob/master/sh...
Re: Building a Shell
#4Building a shell is a great exercise, but honestly having to deal with string parsing is such a bother that it robs like 2/3 of the joy along the way. I once built a very simple one in Go [0] as a learning exercise and I stopped once I started getting frustrated with all the corner cases. [0] https://github.com/lourencovales/codecrafters/blob/master/sh...
Author here, and yeah, I agree. I skipped writing a parser altogether and just split on whitespace and `|` so that I could get to the interesting bits.
For side-projects, I have to ask myself if I'm writing a parser, or if I'm building something else; e.g. for a toy programming language, it's way more fun to start with an AST and play around, and come back to the parser if you really fall in love with it.
Re: Building a Shell
#5[flagged]
Re: Building a Shell
#6Had an assignment to build a shell in a week, how hard could it be?
controlling terminal
session leader
job control
Re: Building a Shell
#7[flagged]
Fascinating that you resurrected an account from 2014 just for LLM spam, were the credentials compromised or something?
Re: Building a Shell
#8[flagged]
Not sure it tells all that much about 'how the OS works'. This is a historical abstraction that happened to look how it looks today with all its numerous warts and shortcomings.
We can easily imagine it done a better way - for all the criticism of Windows, PowerShell gives a glimpse into this hypothetical future.
Re: Building a Shell
#9Bit of pedantry but I don't think traditional unix shell (like this) follows repl model; the shell is not usually doing printing of the result of evaluation . Instead the printing happens more as a side effect of the commands.
[deleted]
Re: Building a Shell
#10[flagged]
Somebody blamed this comment on LLMs, and maybe/probably it is, but I think the first sentence is spot-on so I thought it was worth replying to.
Dealing with the corner cases ends up teaching you a lot about a language and for an ancient language like the shell, dealing with the corner cases also takes you through the thinking process of the original authors and the constraints they were subject to. I found myself in this situation while writing EndBASIC and wrote an article with the surprises I encountered, because I found the journey fascinating: https://www.endbasic.dev/2023/01/endbasic-parsing-difficulti...