Re: [Help-bash] No tilde expansion in [[..]] when reading input with read

[Chris Down]

On 2013-02-25 08:37, Greg Wooledge wrote:
> Ironically, stripping all characters except alphanumeric, underscore,
> and maybe a few other well-chosen bits of punctuation, and then using
> eval, may be the safest and most portable way to go.
>
> IFS= read -r raw_username
> username=${raw_username//[![:alnum:]_.-]/}
> if [[ $username = "$raw_username" ]]; then
>   eval "home=~$username"
>   echo "home=<$home>"
> else
>   echo "Nice try, but no."
> fi

Aren't some of the excluded characters legal on some Unices, though? If I recall
correctly, some are constrained by NAME_REGEX rather than actual limitations in
storing user metadata. Perhaps I remember wrongly.

Chris