is there a way to check if a bash script is complete or not?

Question

I\'m trying to implement a REPL (read-eval-print loop) in bash. If such a thing already exists, please ignore the following and answer this question with a pointer to it.

Answer 1

bash -n -c "$command_text"

...will determine whether your $command_text is a syntactically valid script without actually executing it.

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Note that there's a huge breadth of space between "syntactically valid" and "correct". Consider adopting something like http://shellcheck.net/ if you want to properly parse the language.