On Tue, Apr 3, 2018 at 3:35 AM, Herbert Xu <herb...@gondor.apana.org.au> wrote: > On Mon, Apr 02, 2018 at 08:57:35PM +0200, Denys Vlasenko wrote: >> >> I see this: >> >> $ x='\t'; echo "[$x]" >> [ ] >> >> I'm pretty sure this isn't okay... > > Why not? dash has always behaved like this and this is explicitly > required by POSIX: > > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/echo.html
I totally forgot that dash's echo differs from bash. Sorry. This is the example which is not affected by echo differences: cat <<EOF -\"-\'-\`-\--\z-\*-\?- `echo '-\"-\x-\`-\--\z-\*-\?-'` $(echo '-\"-\x-\`-\--\z-\*-\?-') EOF # bash z -\"-\'-`-\--\z-\*-\?- -\"-\x-`-\--\z-\*-\?- -\"-\x-\`-\--\z-\*-\?- # dash z -\"-\'-`-\--\z-\*-\?- -"-\x-`-\--\z-\*-\?- -\"-\x-\`-\--\z-\*-\?- IOW: if `cmd` outputs \" in here document, it is converted to " whereas bare \" in here document is passed verbatim as \", and $(cmd) in here document also does not show this. Aha... I think `` in heredocs removes \ in commands before running them. Thus, `echo '\"'` would run: echo '"' http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_03 "Within the backquoted style of command substitution, <backslash> shall retain its literal meaning, except when followed by: '$', '`', or <backslash>" I think it should retain \" as \". -- To unsubscribe from this list: send the line "unsubscribe dash" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
