IEEE Standards Interpretations for IEEE Std 1003.2™-1992 IEEE Standard for Information Technology--Portable Operating System Interfaces (POSIX®)--Part 2: Shell and Utilities
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Interpretation Request #106
Topic: mailx and quoting ambiguity Relevant Clauses: 18.104.22.168
POSIX.2 says in 22.214.171.124 "- An argument can be enclosed between paired double-quotes ("") or single-quotes (' '); any white space, shell word expansion or backslash characters within the quotes will be treated literally as part of the argument. A double- quote will be treated literally within single- quotes and vice versa. " It then says that File names, where expected, shall be subjected to the process of shell word expansions.... My reading of this (and confirmed by historical implementations) is that the arguments are parsed, and mailx does not interpret the contents of an argument quoted by "or ". Then, if the argument to the command specifies a filename; the argument is subjected to the process of shell word expansion. This allows the use of commands such as ? write "$((1 + 3))" # uses filename "4" ? save "$(date +%A)" # used filename e.g. "Tuesday" Is this interpretation correct?
The standard is unclear on this issue, and no conformance distinction can be made between alternative implementations based on this. This is being referred to the sponsor.
Rationale for Interpretation