UNIX for Dummies Questions & Answers

Hi there I need to create 1 line pipe that outputs list of files whose second character is digit in reverse order (file is a directory and called /tmp)the way I did
ls /tmp | grep '^.[[:digit:]]*' | sort -r
dunno it does not seem working. I tried to do it with another directory that I am sure contain a file fitting this BRE but it does not work.
So I have 2 question why it does not work (because file is a directory or perhaps because my pattern is written not correctly) and how should I do it ??? Thanks in advance!!!

Code:

ls /tmp/?[0-9]* | sort -r

Code:

ls ?[0-9]* | awk '{print substr($0,2,1), $0}' OFS='\t' | cut -f2-

That pattern is incorrect. If the second character is any non-digit (or even if there is no second character at all), the pattern will match. * allows zero digits to match.

Regards,
Alister

Sorry I don't know why bur it does not working
ls: /tmp/?[0-9]*: No such file or directory

---------- Post updated at 01:19 PM ---------- Previous update was at 01:14 PM ----------

Thanks for the explanation but why "second character is any non-digit" I wanted digit instead I mean I have read that ^ means opposite but I thought it should mean opposite if it is inside []. So, you want to say that even though the it is inside single quote it means not????

Show us the entire script. That behavior would only occur if the argument to ls is quoted or if pathname expansion is disabled (very unlikely).

It has nothing to do with ^. It has to do with *, which means to allow zero or more matches of the preceding character (in this case, any digit, [[:digit:]]). It's the zero part that's important. If the second character is not a digit, that's equivalent to zero digits. If there is no second character at all, that's also equivalent to zero digits (which is why your pattern matches a filename of just 1 character).

Regards,
Alister

It is not a script it is just a pipe

Code:

-bash-3.2$ ls /tmp/?[0-9]* | sort -r
ls: /tmp/?[0-9]*: No such file or directory

Thanks again!
I get your point so is there a way to say for example I want first character to be anything second digit and whatever length of string ??? or I should just do it like '^.[[:digit:]]' like that???