Retrospect: the main door
Self-tutoring about people and events from the past: the tutor reflects… When I went to elementary school on the base, we never entered by a hallway entrance; rather, we had to wait outside our classroom to be let in by …
Author: Jack
[Li|Nux]: braces on the command line
Self-tutoring about Linux: the tutor mentions braces. On the system I use, { Enter will open up a subshell into which you can enter one command per line, as if in a script file. On the last line I just …
Comp sci: awk: if(var)
Self-tutoring about awk: the tutor mentions the if(var) condition. Some computer languages allow if(x) as a condition; others insist an explicit comparison, such as if(x!=0). In my experience, awk allows if(x).
Canadian geography: amphibians: toads
Self-tutoring about Canadian amphibians: the tutor reflects… When I was a kid in PEI, I don’t recall seeing frogs or toads, or hearing them at night. Then again, where I happened to live, there weren’t really any marshes, swamps, etc. …
[Li|U]nix: grep part 3: the + operator
Self-tutoring about [Li|U]nix: the tutor continues about grep capabilities. On the system I use, the + (one or more) operator will work with grep if escaped. With the -E option you don’t have to escape it. Therefore, grep “^t\w\+[.]txt” will …
[Li|U]nix: grep, part 2: a bit about character classes
Self-tutoring about Linux and Unix: Can one use Perl’s amazing regex features with grep? Perhaps some of them: the tutor begins… Perl’s convenient \w and \d work with grep, as-is, on the system I use. Frankly, I’m impressed with what …
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VS-Code: how to stop autocorrect
Self-tutoring about VS-Code: the tutor mentions a workaround. I’m not sure I want to disable auto-correct in VS-Code, but I want to prevent it sometimes, without experimenting with settings. What to do? I find that, if I type a word, …
[Li|U]nix: grep and grep -E, part1
Self-tutoring about Unix: the tutor continues about grep. After reading my post from yesterday, I was in disbelief. I even tried the command there several more times – it works every time. grep isn’t necessarily expected to support alternation – …
Linux: grep, part 0
Self-tutoring about [Li|U]nix: the tutor begins about grep. grep string filename looks for the string in the file called filename. The string can be a regular expression. In my experience, a regex needs to be quoted. For instance, on the …
Retrospect: the massasauga rattlesnake(?), part 1
Self-tutoring about people and events from the past: the tutor reflects…. The massasauga rattlesnake is either threatened or endangered, depending on who you talk to and where. It inhabits wetlands in extreme Southern Ontario and the Midwest (one reason, no …
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