The "Tab in column 1" is a known bug. from https://retrocomputing.stackexchange.com/questions/20292/why-does-make-only-accept-tab-indentation https://retrocomp

The "Tab in column 1" is a known bug. from https://retrocomputing.stackexchange.com/questions/20292/why-does-make-only-accept-tab-indentation https://retrocomputing.stackexchange.com/questions/20292/why... which references https://beebo.org/haycorn/2015-04-20_tabs-and-makefiles.html https://beebo.org/haycorn/2015-04-20_tabs-and-makefiles.html So I gave up on being smart and just used a fixed pattern (^\t) to indicate rules. Within a few weeks of writing Make, I already had a dozen friends who were using it. So even though I knew that "tab in column 1" was a bad idea, I didn't want to disrupt my user base. So instead I wrought havoc on tens of millions. I have used that example in software engineering lectures. Side note: I was awarded the ACM Software Systems Award for Make a decade ago. In my one minute talk on stage, I began "I would like to apologize". The audience then split in two - half started laughing, the other half looked at the laughers.