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Comment by mzs

5 hours ago

Wow I hate* that. I use bracket comments. They're cool cause they are bracket comments, so I use it in scripts to document pipelines. They are annoying cause they are bracket comments, in an interactive shell I have to type more and in TWO places. It's fun to reason-out how it works ;)

  $ echo foo | tr fo FO | sed 's/FOO/BAR/'
  BAR
  $ echo foo | ${IFS# tr fo FO | } sed 's/FOO/BAR/'
  foo

It's nice to have a way to both /* ... */ and // ... in shell scripts though:

  foo \
  | bar ${IFS Do the bar. Do it. } \
  | baz

* in the best possible way, like it's awful - I hate I didn't think of that

3 comments

mzs

Reply
rgrau  5 hours ago

for multiline pipes, it's WAY better to format like

    foo   |
      bar |
      baz

You don't have to use backquotes, AND, it allows you to comment line by line, because there's no backslash messing with the parser.

I also use a last `|\ncat` so you can delete any line and you don't have to worry about the last line being a bit different than the rest

I created a list of similar tricks in https://github.com/kidd/scripting-field-guide in case anyone wants to take a look

  • mzs  3 hours ago

    You'll probably dislike this too:

      $ {
  >     echo foo \
  >     && echo bar \
  >     || echo baz ;
  > }
  foo
  bar
  <^P><^A>$<^F>IFS
  ${IFS#   echo foo   && echo bar   || echo baz ; }
  $ _

    There's good and bad to both approaches. I like how I can use () and {} to bracket things and otherwise every line that end in \ is continued. I line-up on the left with the operator, you with indentation. When you use a # style comment, you have to look up and back and forward to see what the operator is you are continuing over to the next line:

      $ foo |
    bar | # ?Do? *the* $bar$ && [do] {it!}
    baz

    Which only takes an extra neuron or so, but then history...

      <^P>
  $ foo |   bar | # ?Do? *the* $bar$ && [do] {it!}
  baz

    • rgrau  3 hours ago

      aha! I see what you mean, it's indeed a nice option, yep.

      Using brackets like this is something I never thought of, and it's probably why it's hard for me to process it, but I can see it provides nice annotation capabilities, and it's a more self-contained style.

      Thx for sharing!