how to read in user input ~/Downloads and resolve the ~?

[guyuming]

I need to read user input file path such as ~/Download with readline history, and resolve it with realpath.

however, the file_path variable value seems to have single quotation mark around it, so realpath says file not found in Chinese.

but if i echo $file_path, no single quotation mark shown.

How can I resolve user input from ~/Downloads into /home/guyuming/Downloads then?

[grknight]

The reason why the last manual attempt works is because the shell expands the ~ before realpath sees it. The variable never is single quoted.

A way around this is to expand any leading ~ to $HOME after the read:

[guyuming]

[flexibeast]

[guyuming]

i think both "${HOME}${file_path#\~}" and "${file_path/#~/${HOME}}" are like those four-words-Chinese-idioms: concise, but nightmare for many kids

I had long taken for granted that realpath command will translate ~ for me. Literally, you see, realpath, means it, doesn't it?

so, i would suggest to enhance the realpath command with a option, such as --home for this.

[flexibeast]

The `realpath` utility is specified by POSIX.

Tilde expansion is also specified by POSIX.

There isn't one single implementation of the `realpath` utility. By default, on Gentoo, it's provided by GNU coreutils (sys-apps/coreutils). But there's also the `realpath` provided by Busybox (sys-apps/busybox). And more generally, there's the `realpath` provided by BSDs (e.g. here's OpenBSD's).

Since Gentoo isn't the maintainer of any of this software, but merely the packager, you'd need to direct your suggestion to one or more of the relevant maintainers (e.g. here's the coreutils home page). You could also open a bug on austingroupbugs.net to ask that such an option be specified by POSIX (although that wouldn't, of course, inherently result in it being supported by all `realpath` implementations).
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[Goverp]

There's an interesting discussion of handling this issue in Stackoverflow
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Greybeard

[Hu]

Assuming use of bash with readline support enabled, it looks from my limited testing like compgen -W does what is needed: