UNIX

A History and a Memoir by Brian Kernighan:
https://www.youtube.com/watch?v=WEb_YL1K1Qg

What words can you make on a calculator if you hold it upside down? (31 minute of the video). On a modern Linux, command is the same:

grep '^[behilos]*$' /usr/share/dict/words | column

shall return around 190 words.

Copilot explanation of the grep command:

• grep: Searches for lines matching a pattern.
• ’^[behilos]*$’: This is the pattern being searched for.
• ^: Anchors the match to the beginning of the line.
• [behilos]*: Matches zero or more characters, each of which must be one of b, e, h, i, l, o, s.
• $: Anchors the match to the end of the line.
• /usr/share/dict/words: A file containing a list of English words (standard on many Unix-like systems).