A bash/zsh feature, <(cmd), that presents a command’s output as a file name, so tools that want files can read it (diff <(a) <(b)). Not POSIX.
Process substitution
A bash/zsh feature, `<(cmd)`, that presents a command’s output as a file name, so tools that want files can read it (`diff <(a) <(b)`). Not POSIX.