Re: What is wrong with a regex?

[Koichi Murase]

2023年2月4日(土) 13:10 Peng Yu <pengyu.ut@gmail.com>:
> That would be a syntax error as the return status 2 indicates.
>
> $ f=row.txt; [[ $f =~ ^row([0-9]*)(|_x)[.]txt$ ]]; echo $?
> 2

Ah this is interesting, in my system, it returns 0:

$ f=row.txt; [[ $f =~ ^row([0-9]*)(|_x)[.]txt$ ]]; echo $?
0

Probably this is an extension of <regex.h> in my system (the glibc
version is 2.36). I'm using Bash 5.2.9 in GNU/Linux (Fedora 37).

In that case, you can simply use `(_x)?'. I think the following should
work also in your system:

$ f=row.txt; [[ $f =~ ^row([0-9]*)(_x)?[.]txt$ ]]; echo $?
0

--
Koichi