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Comment by wlonkly | Hacker News Reader

Here's a handy delta trick for you, to turn the side-by-side feature on and off based on window size. bash here, other shells left as an exercise:

  function delta_sidebyside {
    if [[ COLUMNS -ge 120 ]]; then
      DELTA_FEATURES='side-by-side'
    else
      DELTA_FEATURES=''
    fi
  }
  trap delta_sidebyside WINCH

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You are probably missing a $ before COLUMNS and export before setting DELTA_FEATURES

Bash is funny with the -gt, -lt etc. operators and the [[ ]] builtin -- bash treats them as arithmetic operators like it does with math in $(( )), and so you provide them the variable name, not the value.

    $ TEST=3
    $ if [[ TEST -gt 2 ]]; then echo "honk"; fi
    honk
    $ TEST=1
    $ if [[ TEST -gt 2 ]]; then echo "honk"; fi
    $

That lets you do things like

    $ if [[ TEST*3 -gt 6 ]]; ...

without having to nest even more double parentheses.

You're correct about having to export DELTA_FEATURES at least once. (I export it outside of the function, but no harm in doing so whenever it's set -- but it's not required to re-export it when you change the value.) Thanks for catching that!

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