I managed to set xpg_echo on in bash and then forget that I did that. I was using echo's behavior with -n to determine if set -o posix had taken effect, when it's completely unrelated. And sh in MSYS2 is definitely just bash with set -o posix on. What I get for rushing.
However, the man page for bash 5.2 only says the following about xpg_echo, in the section about shopt: "If set, the echo builtin expands backslash-escape sequences by default." It makes no mention of disabling option processing. Similarly, in the description of the echo command, we see: "The xpg_echo shell option may be used to dynamically determine whether or not echo expands these escape characters by default." So is that a bug in the documentation? On Wed, Jul 26, 2023 at 10:51 AM Chet Ramey <chet.ra...@case.edu> wrote: > On 7/26/23 10:15 AM, Zachary Santer wrote: > > Oh, that's weird. I just assumed that sh would be running bash with 'set > -o > > posix'. Evidently, not in MSYS2. 'man sh' takes me to the Bash man page. > > Weird. I don't use MSYS2, but that's how it works on Unix/Linux systems. > > > When I run sh, 'set -o posix' has no effect, but it definitely makes > echo > > not interpret any arguments as options when I'm in bash. > > Not quite, at least on Unix/Linux/macOS. `set -o posix' by itself doesn't > affect echo's behavior with respect to accepting options or expanding > backslash-escapes in the remaining arguments. There's too much existing > code to try and bother with that. The `xpg_echo' shell option disables > option processing and enables backslash-escape translation, which is the > POSIX/XSI required behavior. > > -- > ``The lyf so short, the craft so long to lerne.'' - Chaucer > ``Ars longa, vita brevis'' - Hippocrates > Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/ > >
