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I need to install a product for Linux that comes with an install.sh script. Before running it I want to understand what it will do to my system. At the very begin of the script there is something like VARIABLE="${VARIABLE:-""}". I know ${VARIABLE} is reference to access the content of the variable VARIABLE. But I really don't know the purpose of :-"" Can you help me please?

Jens
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Paolo Romagnoli
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    `${var:-other}` set to `var` if `var` is set, otherwise the default `other` is used.. So `v1="${v2:-""}"` set `v1=v2` if `v2` is set, otherwise it sets `v1=""`. Think about how you can set a default or use the first program argument `$1`. `myvar="${1:-some_default}"`. – David C. Rankin Feb 20 '22 at 08:33
  • For all the variable operators, see https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash/16753536#16753536 – Jens Feb 20 '22 at 08:36
  • See: [shell parameter expansion](https://www.gnu.org/software/bash/manual/bash.html#Shell-Parameter-Expansion) – JRFerguson Feb 20 '22 at 13:23

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