chore: ban echo command

[Stratus3D]

Summary

• Add echo to list of banned commands.
• Replace echo calls with calls to printf.
• Correct existing printf calls that were generating ShellCheck warnings.

Fixes: #781

[Stratus3D]

ShellCheck recommends \\n for double quoted strings.

[jthegedus]

LGTM

[jthegedus]

As a general point of discussion, what are your thoughts on:

1. first param to printf always being formatting only (no content)? EG:

   -printf "asdf is self upgrading shims to new asdf exec ...\\n"
   +printf "%s\\n" "asdf is self upgrading shims to new asdf exec ..."

   I try not to be dogmatic about these things

2. re-using a formatting variable for many printf statements?

   +format="%s %s\\n"
   -printf "%s %s\\n" "$asdf_cmd_dir/command-$1.bash" 2
   +printf "$format" "$asdf_cmd_dir/command-$1.bash" 2
   ...
   -printf "%s %s\\n" "$asdf_cmd_dir/command-version.bash" 2
   +printf "$format" "$asdf_cmd_dir/command-version.bash" 2

   Shellcheck does warn against this, but it's docs do mention explicitly ignoring for format reuse.

[Stratus3D]

1. first param to printf always being formatting only (no content)? EG:

Either way is fine with me. Assuming the format string doesn't contain anything that would be interpreted as special characters by printf I think including text in it is ok. In the programming languages I use, I typically hardcode strings of text in the format string, and only use placeholders for values that are dynamic (ie variables).

2. re-using a formatting variable for many printf statements?

If a pattern is repeated in several places, it may make sense to encapsulate the print in a function. Something like:

function command_output() {
  printf "%s %s\\n" "$1" "$2"
}

command_output "$asdf_cmd_dir/command-version.bash" 2

Although I think in cases like this is it overkill (format string is just item, space, item, newline).

[jthegedus]

I disagree on 2 as too often I see the function gets co-opted to do more work and often moved further out of context into another file which exacerbates the problem. Thanks for the food for thought 👍