Shell Scripting

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What's the actual usecase of := in parameter replacement? (lemmy.zip)

submitted 1 week ago by MonkderVierte@lemmy.zip to c/shell@programming.dev

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I've seen : "${DB_HOST:=localhost}" because it assigns the variable if not set (: $… is just to run assignments standalone).

But that has the same effect like DB_HOST="${DB_HOST:-localhost} (use the string if not set), which is more readable.

While something like echo "${DB_HOST:=localhost}" smells from a mile, because it has output with side-effects.

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[–] tribut@infosec.pub 5 points 1 week ago

I've seen plenty bugs that were caused by USER_NAME vs USERNAME and similar in 2026. But if thats not a concern and you think the alternatives are clearer... nobody's forcing you.

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