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@eukara @wjt I've seen it many times, specially in ./configure scripts (auto*hell or not), in fact I wouldn't be surprised to have written similar ones myself either due to:
- Cargo-cult / keeping things consistent with the rest of the code;
- Rules around shell quoting being a PITA;
- Not wanting pure-whitespace/empty-string to be truthful. Like ${foo:-yes} and ${foo:=yes} only acts if it's actually undefined. And how test -n $foo is for empty string;
- Outside of nicely defined commands like test: GNU and it's annoying implementation of getopt.