[For reference, I’m talking about Ash in Alpine Linux here, which is part of BusyBox.]

I thought I knew the big differences, but it turns out I’ve had false assumptions for years. Ash does support [[ double square brackets ]] and (as best I can tell) all of Bash’s logical trickery inside them. It also supports ${VARIABLE_SUBSTRINGS:5:12}` which was another surprise.

At this stage, the only things I’ve found that Bash can do that Ash can’t are:

  • Arrays, which Bash doesn’t seem to do well anyway
  • Brace expansion, which is awesome but I can live without it.

What else is there? Did Ash used to be more limited? The double square bracket thing really surprised me.

  • Daniel Quinn@lemmy.caOP
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    1 year ago

    As far as I’ve seen, they don’t provide any advantage over a string with spaces, which doesn’t work well either when you’ve got values with spaces:

    not_what_you_think=( "a b" "c" "d" )
    for sneaky in ${not_what_you_think[@]}; do
      echo "This is sneaky: ${sneaky}"
    done
    
    This is sneaky: a
    This is sneaky: b
    This is sneaky: c
    This is sneaky: d