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by kingvash 3160 days ago
I've added a counter (of successful commands in a row) to my bashrc. I've seen it as high as 120.

  function promptCommand()
  {
    LAST_STATUS=$?
    # Set title of window to dir, then add new line to prompt.
    PS1='\[\e]0;\w\a\]\n'
    if [ $LAST_STATUS -eq 0 ]; then
      ((successes++))
      PS1+='\[\033[1;32m\][$successes]'
    else
      successes=0
      PS1+='\[\033[1;31m\][0 $LAST_STATUS]'
    fi  
    PS1+='\[\033[0;32m\] '
    PS1+='\w $(date +%H:%M) \$ \[\033[0m\]'
  }

  lastStatus=0
  successes=-1
  PROMPT_COMMAND="promptCommand"
My prompt:

  [0] /home/bar/g3 14:19 $ echo "boo"
  boo

  [1] /home/bar/g3 14:19 $
2 comments

Man, I hope you don't use grep very often (by default it uses exit code 1 when it doesn't find anything).
If it didn't exist in the first place, then you had no business searching for it. You should have just known not to look. :)
I like this joke, it kind of reminds me of the difference between `find_by_id` and `find` in ruby on rails.

In the former, if a result can't be found it will return `nil` but in the latter it expects the record to exist and so will raise an exception if it can't be found.

Python: `Dict.get(k)` (`null`) vs `Dict[k]` (`IndexError`)
that sounds so backwards. `find_by_id` is a lookup, not a search; it seems implied to me that the ID should exist and if it doesn't that's an exception. Whereas `find` is a search and it's not atypical for search results to be empty.
Since I think rails 4 or earlier it's preferred to use `find_by(id: 4)`, but could instead be `find_by(email: "email@example.com")`, or even `find_by(first_name: "Franky', last_name: "Tomato")`.

IMO returning nil instead of an exception for the above is practical for me. Much easier to work with.

Having `find(4)` raising an exception is because you'll typical use it in your member actions for a controller where it's reasonable to want an exception if something can't be found.

It's just Rails being Rails (practical sometimes at the expense of possible interpretation of correctness). You do have to retain stuff like this in your head, but it becomes habit pretty quickly.

This begs the question of what the hell is the point of the bang convention e.g. find! in this case.
I've heard that joke once, but in C++
Negative result is still a result. I sometimes use `grep -r` to check whether "does this set of files contain this particular string?" and "no" is a useful answer :)
twas a joke.
Just pipe the output through cat. By default, the "pipefail" option is not set, so

    echo foo | grep bar | cat
is successful. Of course, this works for any command.
Alternatively and less wastefully:

    echo foo | grep bar || true
Alternatively and shorter:

    echo foo | grep bar || :
>grep

Not to mention tar which is just impossible to get right on the first try.

Especially when disarming a nuke
Nuke-practice is why I only use tar these days.
>cheat tar
This reminds me about https://www.xkcd.com/1168/
just add a '|| true' at the end of every call to grep!
just add a '|| true' at the end of every call!
If you're looking for just mistypes, use status 128.