Sorry, I didn't understand your reply. What I'm saying is this: \? is shown in printf section:
"Causes printf to expand backslash escape sequences in the corresponding argument, except that ‘\c’ terminates output, backslashes in ‘\'’, ‘\"’, and ‘\?’ are not removed, and octal escapes beginning with ‘\0’ may contain up to four digits.” but it isn't documented in https://www.gnu.org/software/bash/manual/html_node/ANSI_002dC-Quoting.html correspondingly after \’ and \”. Please correct me if I am missing the point. 在 2015年9月2日，下午11:32，Chet Ramey <chet.ra...@case.edu> 写道： > On 9/2/15 10:00 AM, ziyunfei wrote: >> bash-4.3$ echo $'\?' >> ? >> >> \? should be added there. > > Backslash-escape sequences that are not present in the documentation are > left unchanged. Posix leaves these up to the implementation. > > -- > ``The lyf so short, the craft so long to lerne.'' - Chaucer > ``Ars longa, vita brevis'' - Hippocrates > Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
