I want to know about expansion of variable and path name and how to demonstrate which one occurs first.

darkshadow56 · 04-07-2020, 01:44 AM

I need to write a script or series of commands to demonstrate what occurs first and how between variable expansion and pathname expansion.
It would be amazing if anyone could show me script.

shruggy · 04-07-2020, 02:06 AM

Seems like a homework to me. From LQ Rules

Quote:

Do not post homework assignments verbatim. We're happy to assist if you have specific questions or have hit a stumbling point, however. Let us know what you've already tried and what references you have used (including class notes, books, and searches) and we'll do our best to help. Keep in mind that your instructor might also be an LQ member.

BTW, in order just to learn what occurs first reading the manual page for your shell would be enough.

berndbausch · 04-07-2020, 02:36 AM

My script (not tested):

Code:

VARIABLE=123
touch VARVAR
echo ${!V*}

darkshadow56 · 04-07-2020, 03:07 AM

its pretty noob thing but i read different articles and handbooks but i just don't get concept so I'm seeking ans in simple language and not in bookish language.
thanks.

berndbausch · 04-07-2020, 04:23 AM

Quote:

Originally Posted by darkshadow56

its pretty noob thing but i read different articles and handbooks but i just don't get concept so I'm seeking ans in simple language and not in bookish language.
thanks.

From the manual page that shruggy linked to:

Quote:

The order of expansions is: brace expansion; tilde expansion, parameter and variable expansion, arithmetic expansion, and command substitution (done in a left-to-right fashion); word splitting; and filename expansion.

I hope you don't call that bookish.

Meanwhile, I did test my script, and it worked as expected.