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> the builtin types are: > [...] > boolean: a shortcut for returning a number (as numbers are booleans). Can someone explain? I can understand booleans being
by MauranKilom 4y ago
> the builtin types are:
> [...]
> boolean: a shortcut for returning a number (as numbers are booleans).
Can someone explain? I can understand booleans being numbers (e.g. #define TRUE 1 in C), but how are numbers booleans in bash?
- EdSchouten 4y agoBooleans in shell scripts are little more than zero (true) and non-zero (false) exit codes.
- MauranKilom 4y agoOk, right. But then it should still say either "booleans are just numbers" or "numbers can be interpreted as booleans, i.e. are truthy or falsy".
- ancientsofmumu 4y agoIt's not that cut & dry, as bash is doing evaluations; 0 and 1 can both be "true" if simply used without an evaluation, but add logic and it starts to matter (grep returns 0 if hit, 1 if not). [[ 0 ]] && echo "hit 0" [[ 1 ]] && echo "hit 1" grep -q 127 /etc/hosts && echo "hit grep" grep -q 128 /etc/hosts || echo "miss grep"